Need advice please - heard too much and am a bit confused.?

Been with my boyfriend for 2 1/2 years. He has a best friend that is female. She lives in a different province. They have been friends for 18 years. There were going to get together about 3 years ago, didn't due to her health. She is constantly phoning him, and wanting to come and visit, they discuss my relationship with my boyfriend, and he phones her and tells her stuff about me - its like a betrayal of sorts - that is the way I feel. Its weird. She visited us about 8 months ago, she wanted to bring her dog - no worries there and then go to buy a vehicle about 3 hours away and wanted my boyfriend to go with her, - I had to stay at home because the dog needed to be with them on the trip! They left at 11 am - got home at 11:30 pm!!!! it was only a 6-7 hour trip. they said it was the dog's fault - she gets car sick??? Lately she has been talking about moving to our town -and being close to him - yes, I found an email that says she wants to be closer to him? and that she is selling her place, may need a place to stay for a while before she buys...I am like what?? our place is too small - its a two bedroom apt....should I stay and trust this guy - or maybe just move on and enjoy my life....HELP!!