Help! Cheating?

I am dating this guy and one of his best friends is a girl. which doesn’t matter to me but for the past few weeks he is blowing of I love you and I miss you(we are in a long distance relationship) he doesn’t want to talk and when I ask why he just says he is sick of texting and when I say I can buy a ticket to visit him but he says no just stay there him and his friend have been hang out more and talking more I kind of think he is cheating. what do you think? Or am I just being selfish and want him all to myself. This boy is the love of my life and I don’t know what to do