I am losing my best friend to her fioncee?

Ok. Here is the deal, my friend met this guy in January and they got engaged in may. Now dont get me wrong here i am super happy for her but, her fioncee seems to be pusing me out of the picture. I mean yea i know that they are goin to be hanging out and such but it feels asthough he does not want me to be friends with her. I am usually only able to hang out with her when he works which is every third day because he is a fireman. And when ever i hang out with them i always feel like the third wheel. He never speaks to me and I just do not feel right around him. I know this probally sounds like i am jelous or whatever buut yeah. Just any advice would be helpful. I really dont wanna lose her as a friend. So please no joking around. Thanks!