Trail of tomato paste to the women's changing station...Too fucking funny!
After reading all of the OP's responses I would have to lay most of the blame on the wife for his humiliation. Yes they both slept around, but open marriages are not uncommon, especially for marriages that have lasted for awhile. The deal breaker was her getting off the pill and getting pregnant by her fuck buddy. Most couples who swing, together or independently, have a birth control rule. She can't even use the excuse that he "convinced" her to get off the pill. "Her body her choice" works both ways here. She made a conscious decision to stop taking her birth control, ergo she is responsible for getting pregnant. From the way it sounds she is fucking black guys simply to get back at the OP for suggesting he sleep with someone else in the first place. My wife and I swing, but there are ground rules. Such as, we talk about who will do who and when, no secret relationships, protection always. While he slept with this woman from work the one time as agreed, she was fucking this black guy non-stop for weeks. If she is still flaunting the affairs in his face, this isn't swinging, she's replacing their relationship with sexual affairs for her own selfish needs. My opinion is take all the kids, they are yours by your own admission, and show her what real humiliation is. By taking YOUR family and showing the world what a "cheater" really deserves. If she's that into being blatantly fucked by any black dick she finds, then your family deserves better.
He already said the other kids were brought in by C-Section so that would explain her not being "loose" from the births.