Not paying his fair share of bills but lavishing the kids with presents is highly, highly manipulative and despicable.

The kids are not mature enough to appreciate all the sacrifices you are making but they can easily see and appreciate glitter.

What this man is doing is underhanded; yikes! He is trying to freeride on your generosity while buying his kids' love with presents.

I think that if you go the way IceCreamKid suggested, your kids' father would be unable to afford gifts because he would need to pick up the tab of "mundane" expenses, and the children would get a more realistic view of who is who in their lives. For the children it will be better. Right now they are witnessing how one parent exploits the other financially but gets away. Is this the lesson you want the children to learn?

As for jealousy - this man is NOT jealous. When he accuses you of sleeping with every man in the office from the boss down to the night cleaner, he does it not out of jealousy or a genuine suspicion, but to improve his standing and his position and feel better about exploiting you financially. If you are at work to pick up his slack, that is not really something he likes to live with. If you are at work sleeping with half of the office, then your being at work automatically means fun and not sacrifices. Simple - by accusing you of sleeping with guys at work, this man relieves himself from whatever remnants of guilty conscience he might be carrying inside him.