Anyone have any success stories

My fiance is 36 and I'm 23. We stopped using bc last April and decided that we wanted to get pregnant. Each month I am devastated by a negative test and af. I've tried logging my temp, using opks, checking cm, the whole 9 but it just stressed me out more. My fiance has 4 other children and one even within the last 4 years so I don't think he's infertile. When j was at the gyno last summer, she said everything seemed fine. Am I just stressing too much? I'm just worried that it's going to get harder to get pregnant as he gets older.