Gavin Rossdale's former lover believes his marriage ended over a lack of trust.

The Bush frontman and wife Gwen Stefani announced their split after 13 years and three children this week but Gavin's ex-partner, cross-dressing singer Marilyn - whose real name is Peter Robinson - said there have been issues for some time because of the rocker's lack of openness.

Claiming Gavin told him about the split in a phone call, Marilyn told ''It really isn't that surprising. This has been going on for years. Well done to them for trying so long!''

Gavin and Marilyn dated in the 80s but he initially denied the relationship after Marilyn spoke out about it in 2009 before eventually admitting all in 2010.

Marilyn said: ''Gwen didn't want to know or acknowledge certain things about him. She wanted to edit his past and he wanted to as well.

''But how do you go into a relationship and not be 100 per cent honest? You can't have an ongoing stable relationship being untruthful or unaccepting. I just don't get it.''

The marriage was also rocked in 2004 after Gwen discovered that Gavin had fathered a child with Pearl Lowe. Although the relationship happened before he met Gwen and his daughter Daisy Lowe was 14 when he discovered the truth, she was reportedly devastated when she found out.

Marilyn said: ''If you're not honest, and especially if you're with someone who is extremely successful and in the public eye, it'll come out of the woodwork.

''And I think the fact that Gavin couldn't be upfront about certain things was the problem. I would be suspicious that the person wasn't being honest with me. I can imagine Gwen would have a similar problem.''

Gwen and Gavin are reportedly seeking joint custody of their sons nine-year-old Kingston, six-year-old Zuma and 17-month-old Apollo.