TTC for 3 years No Luck 😢

I am at a loss with ttc and going to the doctor's for help. The doctor's say I'm not the issue but my other half is because of his very low sperm count. I don't know what to do or how to feel, it is draining me. I finally tried to stop thinking that I could get pregnant and focus on other things. I have 2 children by my ex husband and my fiance has 1 son by his ex. I am blessed to have the 2 boys but we would like to have a child together I'm getting older and just feel helpless.