So.... when you say you've been having an emotional affair, does that mean you have openly flirted and that it's clear she has feelings for you too? This is tricky since she is in a relationship and you don't want to confuse her or rock the boat. That relationship should run it's own course... you know what I mean? I would honestly back off and let her be. It's not very honorable to steal away someone else's gf, imho.