I don't know what to do to save my marriage. Can someone please help me?

It all started when we went to a welcome back party for my husband at his parents house. I had a headache so I took what I thought was tylenol, and it ended up being E. I was talking with my father in law, and one thing led to another, and we ended up going into another room, and having . While we were in the middle of it my husband walked in and caught us. He was so furious that he just left. So this was about a month ago, and my husband is still mad, and not talking to me. To make matters worse I just found out that I'm pregnant. I doubt that the baby belongs to my husband since we have not had in about 7 months because he just got back from a tour of duty in Iraq before this happened. I just don't know how to handle this situation. Can someone please help me? I've told him several times that I was sorry, and that it would never happen again, but he is still mad about it. I'm hoping that we can get ped this because I am still very much in love with him. I just don't know how to get that through to him. I'm sure that since I'm pregnant that it will even complicate things worse. I just don't know what else I can do to try to get him to forgive. Any advice would be greatly appreciated. Please don't just answer to rub in how badly I messed up. I know I made a mistake, but everyone does sometimes so I don't want how bad of a situation that I'm in pointed out to me. I know that things are very complicated. You really could not even imagine how complicated things are. I really regret what happened. Unfortunately, no one can change what has happened. I would really like for me, and my husband to be able to get past this. I am still very much in love with my husband. I sense that he still loves me to, but this is really tough for him. I wish there was a way to turn back time, but there isn't. All I can do is try to mend the pieces of my life back together. Again, any advice or help would be greatly appreciated. -Cindy