Is my boyfriend infertile

I have been with my boyfriend for 3 years. After being together for 1 year, I came off birth control. So for 2 years I haven't taken any sort of birth control. We have sex on the daily, and have both been wanting a baby. We have tried many different positions and I just can't seem to get pregnant. I have a 4 year old from a previous relationship, and she has told me many times she wants a baby brother! lol I feel like we have tried everything and it's just not happening for us. Any suggestions would be greatly appreciated! Thank you in advance!! 😊