Dennis Waterman was secretly battling lung cancer before his death.
TV and theatre actor Maynard, 80, told the MailOnline: "I'm terribly sad that he's gone but I'm really pleased that he did not suffer and died peacefully.
Watch: Dennis Waterman has died aged 74
"He had lung cancer and was really quite poorly for the last couple of years. The girls are very upset."
Maynard and Waterman were married between 1977 and 1987 and shared two daughters, one of whom is EastEnders star Hannah Waterman, best known for playing Laura Beale in the BBC soap.
Maynard said: "The years that Dennis and I were together were happy. Obviously, it didn't work out but lots of marriages don't work out for whatever reason.
"But I'm so glad he had found the right woman at the end. I think he was very happy with Pam and she was with him when he passed."
Waterman died in hospital in Spain with his fourth wife Pam Flint, who he married in 2011, at his side.
A statement from his family said: “We are deeply saddened to announce that our beloved Dennis, passed away very peacefully at his home in Spain.
"The family kindly ask that our privacy is respected at this very difficult time.”
Waterman is perhaps best known for playing police officer George Carter in hit 70s cop show The Sweeney opposite John Thaw, as well as bodyguard Terry McCann in Minder.
He rose to fame as a child actor playing William Brown in the BBC TV adaptation of Richmal Crompton's children's classic Just William stories.
Waterman was also known for his known for his singing voice after he recorded the theme tune for Minder, I Could Be So Good For You, which reached Number Three in the UK charts in 1980.
Maynard acted opposite her ex-husband with guest roles in Minder and The Sweeney.
She has appeared in Coronation Street, Emmerdale, Casualty, Holby City and EastEnders, in which she played daughter Hanna Waterman's onscreen mother Edwina.
Before he married Flint Waterman was also married to actor and Celebrity Big Brother star Rula Lenska, between 1987 and 1998.