Hello,
I am so sorry that you are here and the details of what has transpired in your life the past few months. So he speaks to you like a business partner? Then right now, get down to business. Protect your finances for you and your children. MLCers can run up a lot of debt and leave you and your children with little to nothing. If you need to get a separation filed and child support, get it filed. I dislike writing this because your heart is impacted by this, but he is not focused on you or your children's best interests at all.
The affair partner is a symptom, a serious symptom, but a symptom none the less. Just know that if it wasn't her, it would be someone else. She is just another thing to make him, drum roll or eye roll accepted here, happy. He introduced the children to OW because he wants to make sure everyone can see how happy he is and that everyone can be happy too- even you.
Yes, from time to time, he will reach out and apologize, but from his mindset, he feels that this is all for the best as he has found his long lost happiness. Just know that this is a process and it takes a lot of time.
So the best things to do right now is focus on your self care and the children. You need to rest when you can, eat right, and get your bearings back so that you can be stronger and ready to take care of the kids. As far as he is doing the things with her that he used to do with you, that often happens. MLCers are more focused on just doing and not being creative, so it is easy just to redo the things that he did with you, with her. When your children bring up his life with the affair partner, just quietly shut it down, "Well, that sounds nice, but let's talk about what you are going to do here with me."
Keep posting and know that this forum is a documentation of your journey and we are here to support you.
Take care of the baby and have an awesome day,
(((Ready)))