op, i think ive an idea how ur feeling.
u must be feeln guilty about ur current bf but then it mightnt seem too bad cos you're probably all excited about this new guy, espesh if he has left his gf for you.
its a big ego trip for you too, hes broken someone elses heart especially for you!
i know how i felt when it happend to me a few years ago.
id broken up with my "nice, honest, steady" bf before i kissed this guy (who was a long term crush) & supposedly madly in love with me.
i refused to see him unless he was single & because i felt crappy for his gf, i didnt speak to him til a month later.
by this stage he'd "supposedly" ended it with his gf & i was crazy about him thinking it would all work out.
but unfortunately like the other guys say, once a cheater....
a few months later he dumped me to get back with her, saying it had all been a huge mistake.. lovely bloke eh!
imagine if i had still been in a decent relationship & ended it for him.
just out of curiousity, how long u with ur current bf?
& u say uv known him years... have u always fancied this new guy?