I still cannot get pregnant with my second child after 8 years

I was just wondering if anyone is going through the same thing as me. 

I have a 9 year old and have been trying to get pregnant but never happened again . My fiancé and I broke up for two years , I was in another relationship and was trying for a baby but nothing happened , someone else got pregnant by my fiancé.  we got back together and we started trying after a while but still nothing. I am new to glow. I took an ovulation test when it showed I was at my most fertile, but the test showed that I wasn't ovulating , my periods are regular as well so I do not know what is going on. I had myself tested by my doctor and everything seems to be fine with me . Is anyone else going through this? I can't speak the bfp and other codes yet as I am new to this and feel sort of like an amateur. For those of you who have been able to get pregnant , what did you do ? To those of you trying , what are you doing? I do know that it's in Gods time , I believe that but what if I am doing something wrong ? I just want to add a new edition to my little family and I'd like to get a positive test one day too. I was 20 the first time I got pregnant and now I am 29.Is there something that I am doing wrong ?