Stressed

I caught my boyfriend messaging a girl telling her she was cute and all that my boyfriend said all she would send him back was a “s” I saw she posted that she had“fell in love with someone but could never tell him now” the day after I caught them and asked her what they were snap chatting about. My boyfriend said he only did it because we went through a hard patch but he never wanted anything with her he just was bored and did it because he did know what was happening anymore. We are still together but we were trying for a baby and there’s a good possibility that I’m pregnant. Has anyone ever gone through this and what was your outcome?