ur falling for the new guy because u feel there's something missing.. simple logic.. bt hey look at it this way... 3 years is something... try to analyze what's wrong between the two of you and gently open it up to your guy.. explain to him what you feel... compromise.. and if you find out you're not happy with how things turn out then probably take a shot at this new guy.. be careful though... get to know him first.. there's still ample time to know about this guy.. but be transparent about the guy you had for 3 years...