I think that you already know that you need to leave him.
I've been right where you're standing now.
I ignored the red flags while we were dating... the inappropriate flirting, sneaking off and not telling me who he was with, emails to strange girls.
I thought a ring meant that he truly loved me. So I ignored the red flags while we were engaged... the inappropriate flirting, drinking nights with "the guys" after which he wouldn't call for days, minimizing my feelings and worries that he was being unfaithful.
I thought that marriage vows and children would keep us close. So, I ignored the red flags after we got married... the late night texts and phone calls, innappropriate emails, more "guys night out" while I was at home pregnant.
Looking back now they were more than red flags. They were glaring neon signs that I should have ran. But, I thought he loved me and he made me believe that it was in my head. I didn't love myself or believe that I deserved better than what he had to offer.
Guess what? I know of two confirmed PA's. I would venture to say that there were atleast 3 more but he will never admit to them.
I know how hard it is to walk away. My STBXWH did the same things that your WBF is doing right now. Begging me to stay, tears, threatening to hurt himself, degrading himself as a husband and father. At the time I thought that it must mean he is truly sorry. Now I see it for what it was, deflection.
I'm not saying that every situation is the same. I'm not saying that people can't change. But given your WBF's history spanning your entire relationship, I think its time to cut ties and focus on you. And, as a previous poster suggested, spend these last precious moments with your mom.
**Edit for clarity**Me: BW
DDay #1 Tried R
DDAY #2 Divorcing
Burn everything love then burn the ashes.