“He lies about a lot of little things” well he probably has lied about his ex. Are you serious? Like that’s rule #1 don’t date a guy who talks shit about his ex. Guys only do that when they screwed up and want to hide it/don’t want to admit it to themselves. And honestly? Are you a mom yet? Because what’s wrong with a Happy Mother’s Day? That’s not weird at all, it’s about the kids. Not you. So you should encourage him and be supportive of him being respectful to the mother of his children because that is what a “baby mama” is fyi. A baby mama is just a MOTHER period. A baby mama is a woman like you who had kids thinking & hoping it would turn out ok, and ultimately decided that being a single mom with two kids was better than staying with your husband. Don’t let him pit you against her.