My attempt
Meeting my ex-boyfriend just makes me feel bad for my current boyfriend, so...(connoting "I don't want to do/I didn't do such a thing.")
or
Meeting your ex-boyfriend is just disrespectful to your current boyfriend, so...(connoting "you shouldn't do/you shouldn't have done such a thing.")
っての is a colloquial version of というのは here. If it's やっぱり元彼に会うっての?普通に彼氏に悪い気しかしないし!, の is a sentence ending particle for question, and the only possible interpretation is Majestic-san's one.