What to do...

I have been with my husband for almost 20 years. We have a 9 year old who will be 10 in July. Last year July I found out that I was pregnant. What is suppose to be a happy time for me is not. I discovered that my husband cheated on me with a young girl and she got pregnant a month before me. He explained that the baby could be his or another guy. He also said it was a big mistake and he has no feelinga for her that he wants to keep his family. I have tried to deal with this situation but it is hard. I don't trust him, believe him, and can't stand him touching me. I am lost and crushed. What would you do if you were in my position?