Is my husband cheating on me?

It perplexes that my husband won’t sleep with me. Does this mean he is cheating on me or is he no longer attracted to me? We are suppose to be trying for a baby but he never wants to be intimate. I am beginning to wonder if he is trying to sabotage us getting pregnant because he doesn’t want to have a baby. If that’s the case don’t most men let you know they don’t want a kid. He won’t wear a condom or pull out which occurs maybe three times a month. We were married in August of 2006 and this is an on going problem. I don’t want to look outside of my marriage for pleasure but it is becoming more tempting. I am a desirable woman, when I say that I mean I am not ugly. I will do whatever he ask me to do and he is not very exotic with his preference of love making. What do I do?