Maybe it's me..

Hubby and I have been trying to get pregnant for five months luck. I do admit we aren't having sex enough, but I don't know what else to do. He works 12 hour days more than not, and I am SO tired of doing everything around the house/with our 5 year old, by myself. Sometimes I resent him. I feel awful for saying that, but it's tiring doing everything by yourself. How do I bring this up to him?