Patrick Wolf: A red-letter day for the bad boy of indietronica

His impending gay marriage means Patrick Wolf's new album is very different to its angry predecessors. Elisa Bray meets him

Patrick Wolf is wearing his red stage-suit in honour of Valentine's Day. This evening, he is off to a Chinese restaurant with his boyfriend, William Charles Pollock, to whom he is engaged to be married this summer. It's a fitting day for a conversation about his new album, Lupercalia, which is, after all, about love.

"I've not got my engagement ring yet, it's being made right now", beams Wolf. Will his fiancé wear one, too? "There are no rules. I think we're both going to wear one."

This is the talented performer's fifth album, at just 27. Wolf is exuding an air of self-contentment and fulfilment not usually associated with the singer-songwriter, who has come across as more of a tortured soul. He threatened to quit the music industry altogether back in April 2007, stating on his website that his last shows would be in November that year, and around that time he was pictured in tabloids, spilling drunkenly out of nightclubs. And over the years his clothes became increasingly outrageous, to complement his shock of dyed-red hair.

Then, three-and-a-half years ago, when he had been touring relentlessly around his album The Magic Position, he met Pollock, who works at BBC Radio 6 Music, at a party ("it was love at first sight") and, slowly, things began to change. "I was really, really exhausted and not looking after myself", he says. "I went from one day being a very self-destructive person to starting to realise that it was time to open up and share love."

The self-destructiveness is the result of an unhappy childhood. Classically trained, and a keen musician as a child, he faced years of bullying at school which only came to an end when he was transferred to the arty Bedales boarding school at 15. At 16, he'd had enough. He left his family home in south London, where he'd built up a taste for PJ Harvey, Stockhausen, English folk music and Chet Baker's jazz, and set off to start his musical career.

His debut album Lycanthropy came out to much critical success just after he turned 20. "I did it all through my work and performing, without any form of therapy," he reflects. "Of course it was going to end in some form of public negativity and aggression. Musically aside, it was obvious that my last album was very aggressive; visually I turned more and more into a provocative character more make-up, more hair, more fighting and I just didn't want to do that anymore."

We had been expecting Wolf to release The Conqueror next, a second part to his angry, baroque last album The Bachelor. But Wolf surprised us with Lupercalia, and its romantic theme. Gone are songs such as "Oblivion", with its dark imagery of "guns", dangers" "petrified", replaced by "my love" (I counted 21 uses of the word "love" throughout the album). Lyrically it's his most direct, and from the most personal perspective to date, leaving behind his Angela Carter-style metaphors. With his new-found contentment, a bitter follow-up in the form of The Conqueror would have been impossible.

"That would have been a return to the fighting mode, and I really had done as much of that as I possibly could with The Bachelor. Live it was a fighting kind of set – it was really quite aggressive. I didn't want to be wearing these 30-hole skinhead boots, and musically I didn't want to be making big-noise aggressive music anymore. I was a lot more domestic and filled with love so I had to be honest about that. So that's why there's no more of The Conqueror, no more of the ego, and no more fist pumping in the air."

Today he has a lick of foundation, and his hair is a deep natural chestnut. Wolf explains how he finally decided to deal with his childhood for the first time, investing in long-overdue psychotherapy sessions. There he worked through how he felt as a teenager, the despondency and aggression he still felt towards his tormentors, the way he'd been treated at school and by society.

"I just thought it wasn't, at 27, a dignified thing to be working off energy that you had from when you were 14. So I decided I had to do a lot of cleansing of my soul and not still be the bullied outsider that hated the world and was angry about the way I was treated." Today, he doesn't want to dwell on the past. "I try not to go back so far now. I think it's to draw a line under it", he says, politely putting as end to the subject, over a second glass of white wine.

It was a huge relief for him, both as a writer – it gave him a clean palette to start again – and as a person. At his lowest, he was searching the internet for negative comments about himself, comments which he had indirectly provoked with his extravagant stage personae. They even extended to death-threats. "If you're depressed, you always go and seek the most extreme negative opinions. I remember finding this fantastic thing, 'Patrick Wolf if you ever come up to Leeds I'm going to cut off your head and shit down your neck and put you in a bath of acid'."

He can laugh about it now, but back then it only served to send him spiralling further into depression. "When you look a different way, immediately you think he's probably not even listening to my music, he's just looking at this character on stage. If you're in a weak place mentally, you immediately take that stuff personally, and if you're in a strong place you can laugh at it and think, 'how hilarious'. It's about finding a place as a person that you are proud of yourself. So I found that and I think love, being in a good relationship, is really important. It was about time I had something to dedicate myself to as well as writing, because it helps the writing."

At every junction of his career Wolf has surprised us: after threatening to quit, dropped by his record label Polydor, he returned to release The Bachelor, funding the album via the website Bandstock, selling shares to his fans in exchange for a future copy of his album. It was such a successful enterprise, that he earned £100,000 to make the album, which went into the Top 50 chart. Strange, then, that he should choose to return to a major label.

"To be honest I was pretty much bankrupt by last year. Although I had such great funding for the album, to take a five-piece band on the road for almost two years, I didn't even think about paying my own rent or paying for anything, I just thought about keeping the show on the road and keeping singles coming out. By the end of it I'd worked myself into a really bad place, and my business was about to fold." Luckily for Wolf, and his fans, the demos he'd made landed in the hands of A&R person Keith Wozencroft.

"Just when I thought I'd lost everything and I was about to just go back to busking or something, Keith came along and saved my career and here I am making another album. To just have someone believe in my work was wonderful. I am eternally grateful for that." For someone whose fervent following stretches around the world, to Russia, Poland, Japan and Germany, it's surprising that Wolf doesn't show more confidence. If that weren't enough to boost his confidence, surely his numerous collaborations with well-known faces such as Marianne Faithfull, Patti Smith and Tilda Swinton (who had a speaking part on The Bachelor) is; "that was good..." he giggles. "I get quite speechless about it."

In addition, he was asked by photographer Nan Goldin to write a 45 minute classical piece to soundtrack her work The Ballad of Sexual Dependency at Tate Modern. "That was a big moment for me. If people like Nan really believe in my work I really should believe in my work a lot more."

We meet at the South Bank, close to the south-London home he shares with his fiancé and which is so integral to his love-filled album. Home is just as you'd imagine Wolf's to be: filled with instruments (piano, two harpsichords, violins, viola). He tells me that he has transformed what's meant to be his walk-in wardrobe into a studio to house all his recordings, microphones and archived work from the last 10-odd years. Currently he's focusing on the Celtic harp, piano and the dulcimer.

"Everything I have is out everywhere – it's just to surround myself with what I love." If there is much imagery of the night, and insomnia, in the album, that's because you're likely to find Wolf playing and composing at 3am. "When my fiancé has gone to bed and I'm left alone in the small hours of the night, that's when I really start to play"

Wolf grew up in a creative household. His father is a musician, his mother a painter, and he took inspiration for his latest material from Henri Rousseau's tropical landscapes.

The album has huge commercial potential, its upbeat sound more accessible to the listener. Not that it was written with this in mind, although Wolf wouldn't shun success. "I always think, if you pour everything you have into an album lyrically and sonically – and I'm always happy with two people liking the record – but if the work finds a wider audience it's always flattering. I'm not going to lie and say it's not. I think it's really exciting." So too, is his engagement, which he announced via Twitter.

"Yes", he says hesitantly. "I didn't even think about what it entails in terms of money, and planning. It's a nightmare. I have a venue, but I've been sworn to secrecy." He is keenly following the news that churches will be opened to gay weddings, which would allow him and Pollock to be husbands rather than civil partners. "If it means I'll have to marry him next year and it's the right way then that's the way it's got to be. I want it to be for life."

'Lupercalia' is out on Hideout in May . Single 'The City' is out on 14 March