Ian Ziering is calling it quits on his marriage ... he says he's splitting from his wife, Erin Ludwig, and she says he's already asked her for a divorce.
The "Beverly Hills, 90210" star made the announcement Thursday on social media, saying "It is with a heavy heart I tell you Erin and I are splitting up,” after more than 9 years of marriage.
Ian doesn't make it sound like it's a nasty split, though ... he added, "With our hectic work schedules we could not be busier, and over the last few years have grown apart. She is one of the most incredible women I have ever met and the best mom to our kids.”
Erin and Ian have 2 daughters and he says they will continue raising them together and be "examples of successful co-parents.”
However, Erin makes it sound like there's been trouble in paradise for sometime now. As she puts it, "After 9 1/2 years of marriage Ian asked for a divorce. After having asked multiple times I knew it was time to give up."
It's unclear if either of them has filed divorce docs yet.
Erin says, "Knowing that I am not the person to make him happy makes the situation feel more peaceful. The girls and I are doing great and finding gratitude and love in our new life together and rebuilding."
Ian and Erin tied the knot back in May 2010. This will be his second divorce.