TTC after miscarriage

My partner and I suffered the loss of our angel baby, who we call Charlie at 12 weeks in December 2016.

We are wanting to try again and are TTC but I just can't get over being petrified that it will happen again. My fiancé reassures me and tells me that it'll all be ok and we will hold a baby in our arms when the time is right. I just don't want to see my partner so heartbroken again. Obviously it broke my heart too, but my partner wants nothing more than to be a father as he lost his dad when he was 2. I just don't know if I'm ready but I feel like I'm being selfish by wanting to put things on hold.