How do I get my fiancé to stop cheating?

[David]

People rarely change their basic behaviour much. What he's doing now is what he'll continue to do as long as it works for him.
So one option is that he's simply such a loving guy that he just can't limit his love to one person at a time, even if he knows that it hurts you.
In which case you'll just have to decide if you're willing to accept sharing him with other women. If the other women gets pregnant, you'll be sharing his paycheck with them too.
Or he simply hasn't realized that him keeping another woman hurts you. Some guys do get caught up in this "player" myth that they actually think they're entitled to behave like that.
Or he's simply a no-good cheat.
The key here to me is when you say" I KNOW he loves me. ....How do I get him to .....want me again?"
IF he loved you, then he'd want you. If he's having sex with other women and not you, break it up. Heck, break it up anyhow - he's a serial cheater, and very unlikely to change.
Don't blame the women, he made himself avaliab