Is there a problem?

So guys I have type 2 diabetes and had it since I was about 13 ir 14 I think. My bf and I have sex lets say twice or 3 times a month. I havent been on bc for like 2-3 years now.. but I haven't gotten pregnant? Is there something wrong with me? We are not trying to get pregnant but some women get pregnant with just one time but its making me question why i haven't gotten pregnant yet?