Depression due to infidelity

Charlie
I have always suffered from a level of depression. I thought everything was going good in my life and I was happy. Well ignorance was bliss. I recently found out that my husband has been using the internet to find local girls to cheat on me with. The whole time we have been together. We have only been together for 3 years. We have been married for a year and both decided that we wanted to give our 1st born a sibling. I am currently 17 weeks pregnant and we have a 2 year old daughter. I knew he was unfaithful in the past but I thought it had stopped before we go engaged. He claims it has only been online and that he has never touched another female but I definitely can't trust him now so I don't know what to think. He says he barley remembers doing it because he drinks too much. I demanded he stop drinking or I leave with the babies. He hasn't drank in almost a month and has been more helpful and attentive. I can't bring myself to leave. So I live with these feelings of low self esteem and self worth. Like there must be something wrong with me. Maybe I am not pretty enough or I am gross looking because of the weight I have gained during this pregnancy. Or that this belly is grossing him out. I just feel like how could he do this after we got married. After it took so long for me to trust him when I was pregnant with our first baby. I thought this time would be different. Now he is smoking pot everyday this week. I feel like it is just a matter of time before he cheats on me again. But he is such a great dad. I never had a dad and my daughter is so in love with her father. She doesn't even like him being gone for work. I can't leave. I don't want to. When I said I do I ment it. But I am struggling. I am stressed out, depressed and so anxious because I don't trust him that I can't sleep. Every alert I hear on his phone makes me wonder if it is some girl, or if I go to work (at night) who is coming over. I don't know how people live like this, is it something they just get used too!? I hope that since he has stopped drinking that that will be the solution to his infidelity because he was getting out of control. But once trust is broken it can never be the same. We are starting therapy and the therapist says we can work past this and come out even stronger but only time will tell. Until then my sanity hangs in the balance.