The DC (nearly three, and four and a half) wanted to watch the X Factor today, so I told them that they could, provided they were bathed and in their pyjamas by the time it started, so that they could go straight to bed when it was finished.
At 7.30 when I called them for their bath, they wouldn't go, and DH wouldn't back me up in getting them upstairs. I then told them that if they didn't come upstairs and get bathed, there would be no X Factor and they would go straight to bed.
At 7.53, DS1 wandered upstairs for his bath, and I said it was too late, and he was going straight to bed. He became hysterical and DH gave him lots of guff about the fact that he would let him stay up anyway, but Mummy's insisting he go to bed. (DS2 has been unbothered by the whole thing.).
DS2 has now calmed down sufficiently for DH to read the bedtime story (I'm not doing it because I have a frightful tongue ulcer which makes speaking incredibly painful, and may also explain the extremely short fuse I'm on tonight), and I'm sitting fuming at the computer.
What time does/did X Factor start? Is it 8pm? If yes, I probably would have let him have a quick bath and then watch it. I think it's probably not his fault, as he got mixed messages from you and your DH. TBH I think what your DH did was very wrong, he really should have backed you up, even if he didn't entirely agree with you. And telling your DS that it's your "fault" for sending him to bed... . He is your DS' father, not his friend.
If there was any more than about two minutes gap between the "come now or you're not staying up" and the wandering upstairs then I think you were right. You'd warned them twice at least and they hadn't done as they were asked. As the others have said, though, the problem here isn't your children, as much as your husband undermining you.
I was letting them stay up because it's a Saturday, and they did enjoy X Factor when we watched it last weekend after arriving home from holiday - we had such a nice time all curled up on the sofa and I thought it would be lovely to do it again, provided they were, as they were last week, in their pyjamas when it started.
There was a gap of about 20 minutes between the "come now or you're not staying up" warning and DS1 wandering upstairs, scootergrrrl. I feel awful for the upset that my following through on my warning caused (DH thinks we should have just put them in their pyjamas without a bath, and let them stay up anyway), but I think it's very important that we don't make empty threats or promises to the children.
As for DH undermining me - he used to do it a lot when the boys were younger, but he hasn't done it on this scale for ages.