I'm sure you've read a lot of comments telling you to dump him. Here's one more saying the same! Never mind his reasons for being a jerk, this guy is actively trying to make your life worse. YOU CAN'T BE WITH SOMEONE WHO IS TRYING TO DAMAGE YOUR LIFE.
he's been telling two of his male friends I slept with my boss in order to get this job
Ruining your reputation. That's is horrible and totally unacceptable. This is something that should have been confronted and should have been an conversation that ended with you telling him, "I'll give you a 2nd chance but if something like this happens again you are finished."
I got called into my boss' office to discuss maternity leave, because my fiancé told him I was pregnant. So I had to go through the embarrassment of proving to my boss I'm not pregnant
Ruining your job. Unacceptable. If he'd have been working on the 2nd Chance rule, this would have been the end of your relationship with him. But forget the second chance - this guy mucked with your JOB. There's no second chance for that kind of nonsense. Automatic dealbreaker; game over.
he told me he wants me to quit my job, and that he has thought about leaving me because I'm no longer 'wife material' and 'won't be domestic enough'
As if you needed another reason to give this guy the boot to the backside, here you are.
I don't want to leave him because my daughter is used to him
But... but... but... is this the guy that you really want your daughter to get used to? A guy that's so insecure about his wife earning more than him, and yet gladly spends your money at the same time, a guy that spreads particularly nasty lies about you to his friends, a guy that undermines your reputation at work and destabilizes the security of your job, a guy that wants "wife material" and wants you properly "domesticated".
KICK HIM OUT IMMEDIATELY. You deserve so much better than this. Hell, everyone in the world deserves better than this by default. He may be sweet 90% of the time but that does not make him a decent man. He's not a decent man. He's giving you small reveals of his character. Look, this guy will most definitely get worse after marriage - you can already see where this is going, this guy wants a domesticated wife/servant. Kick him out.