How do I make him understand no contact is a necessity?

Okay, I am at my whits end and I do not know if I am being overly sensitive or if I am in the right. Long story short, my husband left me for another woman a few months ago, and we agreed to try to work it out (married for almost 8 years, two children), he moved back in 1 month ago. At this point I do not know what he told the other woman, and I do not know what he is telling her, but for about 3 weeks he had no contact with her, now he is texting her back, talking to her at work, and most likely talking to her on the phone. And yet everything is perfect at home, I know where he is so unless he is being physical with her in the middle of a nasty factory, he is not being physical with her. He is attentive, kind, caring, he was a good father but now he is a better one, he is complementing, he has regained his desire to hold me not just have sex with me. I do not know if I am being a psycho, he says that she is just nice and downplays how much he talks to her, i can not really be sure how much because they work together, however the one day he had off from work he spent a good hour texting her. I do not know what to think, he has even said he wants me to stop divorce proceedings. So should I except his story that she is a friend now, she is seeing other people and she is just nice?