Quote Originally Posted by TyBuff
Have you tried just telling them "NO I am not interested!!!"? Maybe just the straight approach would get them to back off the gas pedal.
That is the best advice given on here. Noone should be flirting with a guy who is in a serious relationship. If they are, then you have to question what sort of person they are. That's if they know you are in a serious relationship?! Just tell things straight and all issues should be resolved. If not, then they are being bang out of order and are obviously a bit messed up!