It sounds like the current bf is not devoting attention that you want and you find this guys attention flattering.....
If the situation was reversed ..........would you like this done to you?
Just a thought...............
I meet a lot of guys where I work who are intrested in me....... I always tell them up front that I am engaged.............and that said........... I would like to feel that they like me as who I am.... I get their ### , call them to say hi and chat.... and I always introduce to the future husband..(NO HIDING).......and they call him

( makes me wonder if there is something I should know about

) I find it flattering that people do not see myself the way that I do.....