Getting pregnant

Hi everyone ,

Me n my boyfriend of 3 years are trying to have a baby but it seems like nothing's working we have been trying for a year now an nothing.. we have started eating healthier working out n other stuff. Dose anyone have any good ideas that can help us. I already have a son with somebody else an he doesn't have kids but He really wants daughter's. He also wont go to the doctors to see if anything is wrong dose one have any advice.?