Heartache- I need to give away one of my cats?

I got divorced and ended up with our 3 cats. My ex-wife cannot take them, though she was the reason we got them. For various reasons she is not an option. I can handle 2 but 3 is just getting to me. I figured I can give away one of the females who likes being on her own anyway. She is incredibly affectionate and loving and I want to make sure she ends up in a good home. How can I go about this?