What do you do if you're dating a man and you don't like one of his kids? He and I had been seeing each other for six months or so before he introduced me to his children. At the time, I thought this was a great idea—wait until we get serious. Kids don't need to meet everyone Daddy's dating. But when we decided to be monogamous, we thought it was time. I was already in love with this man, and we've since decided to marry.
His son, 12, is a sweetheart. He's polite, kind, a doll. Unfortunately, the daughter is a problem child, and apparently has been since she was born. There are learning disabilities, but more than that, an intrinsic cruelty that makes me uneasy. She's only 10, but has a chilling capacity to know exactly what buttons to push. And push them she does. Not only with me, but with her brother and father, though her dad seems unwilling to see this. In fact, I think the fact that I stick up for him is one of the reasons his son likes me. I should mention that their parents' divorce was not ugly, and they're still quite friendly. I had nothing to do with their split, so it's not like she resents me for that. I'm having second thoughts about marrying him; every time I try to talk to him about it, he gets defensive, saying "She's only a child!" Which is true, but so? Any advice? He shares custody with his wife, and now that we've moved in together, I see her three days a week.
Did you ever see that clip of Louis C.K. calling his 4-year-old daughter an asshole? It was hilarious, not remotely cruel, and a rare bit of honesty from a parent. Because really, there are a lot of little asshole kids running around out there. You don't mention that this one is torturing animals or peeing in anyone's Cheerios, so she's probably just a little too smart for her own good, possibly on the spectrum, and kind of a bitch. You sound as if you don't spend much time around kids, which might be the problem. They're not small adults—they're another species. Some are good little monkeys, some are naughty, but you can't expect them to behave like reasonable adults, because they're incapable. (Just wait until she hits puberty!)
You and Mr. Man there need to sit down and have a big, fat talk. He's probably taking your criticisms of his kid personally—and really, there's no "good" way to critique someone's offspring. I've seen parents go into white-rage mode when someone (um, me) suggested their darling might want to quit kicking the back of my seat. But you guys aren't strangers on an international flight—you're going to be co-parenting these kids, so he needs to help you.
Bear in mind that just because you didn't cause the split, your presence is a flesh-and-blood reminder that Mommy and Daddy are done-zo. So try to be patient, but don't be a pushover.