So op you are in a relationship that had problems before any of this started. In fact your relationship was so unstable and volatile, that, despite having two young children, you chose to separate/be on a break. You yourself admitted that the pair of you should have stuck it out together and communicated with each other but you were ‘too irate’ to do that. Hmmm, not a good starting off point for the ensuing drama.
So next he goes off and finds the OW; apparently he and she see each other only three times, on two of those occasions they have sex but he was wearing a condom .....so no problem there.
Next you and he get back together, there’s a surprise ‘love child’ announcement and, well I could have said it all goes downhill from there.......except the pair of you seem to have been a good way down the hill already.
So on various post of yours I’ve read ( I’ll admit I haven’t read the full read but I have read all the OP’s) that all previous problems between you and him are sorted, he got a ‘bollocking’ from you and the family for his actions, but it’s ok because ‘everyone makes mistakes’ He knows he’s done wrong and ‘seeing him so broken tugs at your heart strings’
You go on to say ‘it’s just her causing all the issues’
OP how can you readily admit that everyone makes mistakes without affording the OW the same leniency?
You may have seen all the messages between them but truthfully you have no idea what he said to her in private. He’s well and truly proved now he’s not trust worthy so how can you believe what he tells you?
You say she’s been ‘very protected’ by her family, whom she lived with, and when they found out about the pregnancy, they threw her out. Yes she could’ve aborted but maybe that’s not her values or culturally acceptable to her.
So here the OW is - someone who met a guy, listened to him, liked him well enough to sleep with him, he went back to his wife, then when she finds out she’s pregnant she’s made homeless after being thrown out by her family. I am not at all surprised she’s ‘got issues’ and has acted irrationally.
All your hand wringing OP is based on your allegedly comfortable life being thrown into jeopardy by her actions when in actuality your marriage was on the rocks beforehand.
The marriage, your home and the future of your children wasn’t respected or valued by your husband. Once he was away from the family he spent time having pleasure with someone else rather than trying to figure out how to make things better for you and the children.
I get that you’re frightened of leaving, yes that is incredibly scary and traumatic for your children, but it is better than them living in the emotional fallout of a marriage that was already in a state notwithstanding all of this.
You’ll only get your head straight once you have established a stable life, for you kids most importantly. Children are always better off with parents who are emotionally balanced even if that means the parents live apart.
I feel you are a bit deluded when it comes to thinking you have fixed all the early difficulties and now it’s just the OW and baby that are the problem. The actual problem is that you are too afraid of what you might loose if give yourself, and the children, the space you all need.