Sorry for your situation, but I can see your anecdote, and raise you one. My son is doing great with his relationships, even though his mom and I divorced when he was 4, and she is still an asshole.

I also have had two good friends who stayed in loveless marriages and their kids are totally fucked up.

As always, "it depends" - particularly on the parents and how they intereact with their children - whether they stay in the marriage or not.