How can i maintain relations with my ex without feeling to affectionate?

we broke up for ...well i dont really know why but they werent really relationship problems, so we broke up on good terms its been a few months and im most of the way over her, but when i talk to her, i cant help but feel (every once and a while) that afectionate "my girlfriend is so cute" smile creep up my face. i hate it....how cani maintain a friendship with her while still getting over her (im close to done with that anyways) and without finding a nother girl (not impossible just hard to find)