Is my friend trying to steal my man?

Sorry this is soo long!!! Ok so I have been dating my boyfriend Dylan for a year and 3 months we love eachother and would never do anything to hurt eachother. My friend Bre didn't like him for the 3 years she knew him before she moved away. While she was gone they talked but just about the hey how ya doin thing Once she came back Bre has been ALL over him. A few examples of the many are 1. the other day at a party I couldn't attend she went up to him and told her that at her new house they have a pool so "Maybe just me and you can go hang out and have a pool party."(Bre's words straight out of her mouth) At school Dylan's ID was over his sholder so she has her "Sexy" flirtasious smile on and brushed her hand down his chest putting his ID back to where it belongs! Another time at lunch Bre went over and sat next to him while I was on the other side of the table took my spot wouldn't scoot over so I could sit there and she kept scooting closer to him. Also when she has her own jacket in her backpack that I just saw her put up she asks him for his jacket while im outside with them in the snow wihout a jacket. I have talked to Dylan and asked him to ignore her but he says dont worry about it babe I love you and dont even like her. (He wont stop talking to her even if I ask him) Please give me advice on what to do about Bre.