My ex knocked someone up

So early this week i found out thru a friend that my abusive ex and his gf were pregnant. When i found out I cried me and my fiance have been trying for almost 6 months and it still hasn't happened. But he got this chick knocked up in 3 months. Whats the most irritating for me is that the girl he is with is the girl that he cheated with and now they are having a kid. The one thing in life i have always wanted since i was little was kids I wanted to be a mom and it never changed even when i was a nanny and i delt with sick kids or kids that didn't behave or when i did over night babysitting it never changed i always thought i just cant wait till it's my own kids and im so happy for everyone that gets pregnant on here it give me a little hope that maybe it will happen for me but everytime i see a negative test it brakes me. But im not going to give up hope and eventually i will have kids even if it ends up i adopt eventually that dream will come true.