do you guard yourself from kids?

Hi there I'm really new to these forms, I'm Jacci I'm 43 yrs old. Childless , but my husband and I are going to start the process again, for the fouth time, we have had three failed adoptions,one private,one indepentant,and special needs.Each time the birthmother decided to keep their baby or worked to get back her child.SO we are trying again because... (we are CRAZY!!! just kidding 80) But what I wanted to ask, is am I the only one out there that no matter how deeply I want the one thing I cannot have and want it more than life itself,...It's hard to admit it but around my nieces and newphews, and other friends, kids I put up this emotional wall..I HATE it but I just have been "the bridesmaid" and not the bride so many times I feel this sadness inside that the kids can feel,I'm sure of it,being adopted myself putting up walls is so easy and feeling somewhat detached is always inside of me, it can be very hard to connect with the kids that I love so much!! has anybody else felt or feel this way around other people and especialy other people's children ??? I hate feeling like "the bad Aunt" because I'm so sad inside :confused: