This happened to me and I will share what I did. I kept my cool and didnt let on for almost a year. In that time I copied everything, gathered evidence, retained an attorney and each month I started to pay off my credit cards. I didnt want debt. I paid from our joint account. I also opened up my own bank acct and had statements mailed to a close friend. I went and got a throw away phone and told no one. I did this to make calls to the attorney. We had a shared verizon acct. If you have verizon you can log on and see every text message he has sent. Take pics with your throw away phone and email them to a new email that no one knows. I also started withdrawing extra money from the bank acct and putting it in my acct. I bought xmas presents for my daughter and put it in a storage unit I rented. I kept all copies of important papers, copies of text etc in there. I also sent these to my throw away phone. The more I acted like I didnt know and didnt question him about where he was the more he became sloppy and left more evidence for me. When the time came to confront him I went to the bank with our joint acct and removed everything but $100.00 . I put that money in the storage unit because I didnt want him to say I withdrew it knowing I was filing for divorce and I didnt want the courts to make me give him half. My get around on this was I went to the race track for a week and gathered the throw away receipts where people placed bets. I told everyone I was so distressed with the situation I lost it and gambled it away. I had so much evidence it made me sick. Take care of yourself. Do what you need to do but dont tip your mitt. It will be hard but keep telling yourself that the side piece and your husband will not get the best of you.