Problems getting pregnant

So.... My husband and I have been trying to get pregnant for over 5 years now. Back in 12/2013 we got pregnant then a couple of days later my body started expelling the baby. I have a 7 year old from my previous marriage. It feels like there is something wrong with my body, and as to why I'm not getting pregnant. I did have mirena inserted not too long after I had my first. So, I don't know if me not getting pregnant has something to do with that or not. My question is: Is it me, my husband, or both of us???? I have been checked out, and the gyno said everything looks fine, but still that doesn't give me an answer as to why I'm still not getting pregnant.....