getting very discouraged

I'm crying y'all. My husband says "it's still early, you know that" but I don't think we are ever going to get pregnant. I almost want to go on birth control so I'm not disappointed every single month. This hurts. Very badly. 

We have no kids together yet but are blended with his 4 and my 2

I get so frustrated that his first wife and he had 4 children and she is a drug addict who doesn't care for them and I just want to have 1 with him. Why..........