Your story reminds me so much of my boyfriend. He and his ex-wife met in college, married too young, and never really liked each other much. She "accidentally" got pregnant while supposedly on birth control. He resigned himself to staying until his son was 18 and then getting the hell out. When she mysteriously accidentally got pregnant with their second child he thought of it as "time added to his sentence." They were very mututally abusive for 18 years until she told him on their anniversary that she didn't want to be married to him anymore. She didn't really mean it and was pretty shocked when he went through with a separation. He went to therapy, got diganosed with Narcissitic personality disorder, got sober and realized that she was way worse of a person than he was and they needed to divorce unless he wanted to drink himself to death.

I'm convinced she has NPD too and possibly BPD as well. She got custody of both kids and moved to another state where she continued to f*** up her life because she refuses to get any help. I have been dating my boyfriend a little over a year and one of the two kids has already come back to live with him and the second likely will soon because the ex has deteriorated to the point that a judge will probably take custody away. All that being said, we have a wonderful healthy relationship, we are deeply in love and support and respect each other. He did not believe that real love was even possible when he split with his ex. We rarely fight, the sex is great and frequent, honestly I could not have imagined a better relationship. I'm thankful every day he had the strength to go through with the separation when she brought it up. Everyone's situation is different and only you can know what's right for you but your kids will figure out that you two don't like each other, and you're postponing the chance at a happy, loving relationship until they're grown.