Was I wrong?

I am 5 1/2 months pregnant and me and my boyfriend has been together for almost 2 years. Every since I found out that I was pregnant we have seemed to grow apart extremely compared to how we were before. I've having a feel that he was talking to someone else, so when I went over to his house last night I decided to look through his messages and I found exactly What I didn't want to find. He has been Ralph v to some girl telling her all the same things he use to say to me. I haven't confronted him directly yet and I'm struggling with myself if j really should do it.