trying to get pregnant!

My husband and I ah e been together for 4 years and married for 3. We've been trying to get pregnant for 2 years now. It's definitely starting to get very discouraging. My husband already has 2 other children from previous relationships. I, on the other hand, do not have any bio children. I want to be a mommy so bad! My husband has to have testosterone shots every 2 weeks. He refused to go to the doctor to see what's going on. I have already been checked. I've considered divorce because this is an extremely important matter to me. Any one else struggle with this?