As a kid I begged my Mum to leave my father and she didn't. Worst decision of her (and my sisters' and my) life. But that was because he was abusive, including towards us. So staying with him certainly wasn't for our sakes, but because of her fear and weakness.
DP and I have stuck it out during our 11 year relationship at times because of ties - finances, our child, our businesses. From DP's side for a while definitely because of how attached DD is to me and what he was afraid of missing out on with her. And we were both very unhappy for a time. But we have both worked it out (not necessarily at the same time for ages!). We came out of it. It wasn't all terrible, all of the time, but it honestly took a couple of years.
It was worth it. :) A relationship is there for practical as well as emotional reasons IMO and sometimes it's the practical stuff that keeps you going, including kids.
And FWIW DP's parents divorced when he was 5. Neither of them have very good relationship skills and he's had to learn those with me (as have I). His Mum had a particular knack for being in bad relationships, so just because she left his Dad he wasn't spared that. Sometimes the issue lies within yourself, it certainly did for DP and I. But with my background I do realise that is not always the case (although Mum's choice of an abusive partner is related to her own issues).
