heres a few things:
does your boyfriend know about this?
if not, you should talk to him about it, and tell him how you feel.
if they were hanging one in each of your hands, who would you save right now?
"it was like we were back together b/c we held hands & he put his arm around me 24/7 while he was here. We're still as in Love as ever, for sure. But I've got a bf now and I refuse to cheat."
that sounds kind of like cheating to me.

to answer the question, be with who you care about more.