5 YEARS TTC

I have been with my husband for 7 years and married for 3. We both have children from previous relationships. I have 2 boys and had 1 miscarriage between my 2 boys. My husband has a daughter. I am not understanding why we can't conceive. My husband had blockage around his heart which caused him to have 2 stints put in about 4 years ago at age 22. Could this cause him to become unable to reproduce? We have decided to start seeing doctors and he has his first appointment next month. We have also decided that if we can't conceive within the next year we will start looking into adoption. Idk what I was really asking here but I think I more less just needed to VENT my situation. Thank you for reading