Trying takes forever!

Brittney
My husband and I have been together since we was 13 going on 14. We are now 19 going on 20. Married almost 2 years. Trying for one year and 6 months. He was told he had low chances of having children. We try all the time and nothing works. I'm so close to just throwing in the towel. Help. :( I need advice. ....