I'm on the "boyfriends come and go, but you chose to bring this dog into your life, forever, not just as long as it was convenient" bandwagon. Maybe this is offensive or rude, but I can't see giving either of my girls up for ANYTHING. Callie has the most even temperment, and has never ever met a stranger. Lola can be snobbish about people, and she has to sometimes get to know them on her terms. Once they are friends, they are friends for life, but it is my responsibility to ensure that every person she meets is a good experience. I know she is scared of children, which has to do with her "breeder" not socializing her properly and allowing her to come home with me too early. So I never ever force her to meet children. Instead, when I know we will be somewhere where we will likely run into children, I take treats. Anytime little kids run up to her, I stand in front of Lola, and explain to the children she is scared of them. I instruct them how to politely introduce themselves to Lola, and I give them treats or kibble to let Lola eat out of their hands. Thus, I control Lola's interactions with children so they are always positive experiences, and she comes to associate "big scary monster children" with "yummy food and soft pats on the head". It is a slow process, and I have to respect that some children are too little to understand how to interact with her politely. In those cases, I hold Lola & tell the children she isn't feeling up to company at the moment. Each situation is unique, and there are just some children Lola doesn't feel comfy with, so I don't force the issue too much.
I guess my long winded soapbox is to say, have patience, take baby steps, and do what's best for the being that you committed to caring for.