Not to sound defeatist but the pain in your post is overwhelming. I would really start thinking about protecting yourself financially and looking at the support around you for you and your children. I can't empathise with a man, especially a new father, who is willing to put his wife through this type of constant pain..sorry..but in my opinion he is being selfish.
Poly can be wonderful..but it can also be a convenient excuse to mask flat out shitty and immature behavior. Lots of guys feel the strain of having a wife/girlfriend who is pregnant and feeling like their needs aren't being met...I've been there and so have many of the men I know...I call them men because they sucked it up and got through it without crushing the hearts of the woman they love for the sake of sexual gratification or because they felt lonley.
A) He fucking cheated on you....there is no goddamn positive aspect of cheating accept for the person who is getting their rocks off and who ever is enabling that. People make mistakes..and then they deal with them and learn. He's made his mistake, time to learn.
B) He expects you to embrace the women who enabled him to cheat on you...tell him to give his head a shake and grow up. You're a new mother and she is his mistress.
C) Where the hell is this women's sense of morality and concern for you? I know what it is like to look in the mirror and know I am having an affair with a married woman and "directly" hurting her husband. She should be walking away from this. If everyone was as blind to the happiness and health of others the world would be a very shitty place. The world would be ruled by aggressive takers, people only concerned for their own well being and hiding behind a veil of philosphical "I can't be accountable for someone else's reaction." Bull fucking shit.
This isn't poly...this is a fine example of selfishness....obviously this thread is not making me happy. I am leaving it because there are so many triggers in this.
Please look after yourself...you will get all the family support in this. I don't usually say this, but you've got all the power...you just don't realize it.
Playing the Game of Life with Monopoly rules.
Monogamy might just be in my genes
Poly Events All Over