Gavin Rossdale comes outta the closet!

Gavin Rossdale reveals after two decades that he had a gay relationship, but here’s his take: What’s the big deal?

The 44-year-old British musician has been married to Gwen Stefani for eight years, and they have two children together. But cross-dressing English singer Peter Robinson, better known as “Marilyn,” has claimed sexual congress with Gavin for years — and now Gavin wants everyone to know the truth.

Namely, yes, he had an affair with Marilyn — but it was just a one-time thing. And, Gavin says, he was young and “learning.”

“When you’re 17, Jesus Christ. I don’t think there’s anything strange about any form of, you’re learning about life,” he tells Details magazine in the November issue. “It’s a part of growing up.”

Even though Marilyn claims the affair went on for several years, and that he was asked by Gavin not to talk about it — Gavin tells the mag that’s not the case at all.

“Yea. That was it. [a one time thing],” says Gavin. “You have to know what you like, and I know what I like.”

News broke of the affair in singer Boy George’s 1995 book Take It Like a Man, but even years later, Marilyn says they really had a connection.

“We were together five years,” said Marilyn. “But it felt like 40.”