Trying to conceive

Have been trying to conceive since December. Have hit the mark almost every month on ovulation time but so far no luck. He is a bodybuilder so of course he takes things that will hurt his capability but I still

Can’t help think it’s something with me. I have three kids already, not by him. He has one of his own too. I’m 30 years old. Idk the possibility of something causing me to be infertile. Have an appointment soon to start checking things out but really can’t help but be down in the dumps about it all.