Am I wrong?

Dakota

Ok so i found out almost a month ago my fiance has been cheating on me since a week after he proposed up until our son was almost a month old. He proposed July 20th the cheating started July 28th. Our son was born September 25th. I found out on October 17th. Well after a week or two we decided that we wanted to try working it out (yes I know i deserve better, yes i know most people say i should leave because "once a cheater always a cheater") but i have a habit of giving more chance than people deserve. But the last couple days i keep thinking about testing him to see if he is actually going to stay loyal but I was talking to a couple of my close friends and they said if I do im in the wrong. I guess my question is am i wrong for wanting to test him?