I wish men didn't act like boys

I am a 21 year old guy who has been seeing this other guy for about a year now. We are going to say his 33 and his name Jim (not real age or name). Ok so me and Jim have been together for about a year now and I just found out he was cheating on me. But to top it off he was cheating on me with a coworker. I moved  to the area to be with Jim because we wanted to take are relationship to the next level. My coworker was the only person I started to trust to be here and look what that dose to me. I tried to talk to Jim about it but he swears nothing is going on. I have proof between text pitchers and they were found together in are bed. Most men I have ever been with have meant next to nothing to me but Jim was different. Or so I thought, because at first it was like a normal relationship we were friends then became more. Till I found out the truth he is only with me for my money because I work 2 jobs and pay all the bills and why I'm at work he dose this. So to all the guys and gals that are have relationship problems I know what your having to put up with and I am deeply sorry to you all. How I see it is if you thank your partner is cheating they are and if you find even one little strand of proof confront them and leave there ass high and dry.