What should I do?

This was on my husbands email one year ago. The worst part is the date of the email was two weeks before my due date our son. I just found out now due to me looking in his sent email.  At the time we were engaged. We just got married in July. I felt disappointed and disgusted. Before we got married we were separated for a week. I left because I found he was talking to girls on Tinder and a woman from work. No sexual orientation that he told me.