I keep trying...

So I'm getting married next year to a very amazing man (my dream) and we want to start a family right away. We both LOVE kids and it's our dream to be parents. We always have unprotected sex and we have for a long time. We both know it's not him, considering he already has a daughter, I'm just wondering what are some things I could do to boost my fertility? I know having sex during my peak times is something, but is there anything else? I'm not even 30 yet but I'm beginning to think it might have fertility issues. My period is usually always on time and lasts 5 to 7 days like usual.