me and exH are mostly pretty friendly now, we have been split over 5 years and i am remarried with another DC
he has been going out with his girlfriend for about 6 months now, and every time he picks up his DC (aged 5)
DC likes her and she seems ok, other than, she HAS to come in with exH when he collects DC, and they both just kind of stand there 
while i am getting dc ready and its all awkward, she doesn't speak really other than to say hello. and she stares at me, even my DH has noticed. i just pick up this uncomfortable vibe from her as if she doesn't like me. (i might be being paranoid here but its the impression i get)
she is by no means his first GF since we split, he has had quite a few and most i have met and got on with fine.
also a couple of months ago i friend requested her on facebook and she rejected it. which i found quite strange as she comes in my house every weekend and also has my son every weekend with my ex. obviously its entirely up to her who she is friends with on facebook but i just found it a bit odd.
its just weird, if she doesn't like me for any reason then why not just sit in the car, exH only comes in for a few minutes.