boyfriend has an opp sex friend

Hi to anyone reading i don't know if i have a problem or not but i feel i do that's why i'm posting it has been bothering me for awhile now i live with my boyfriend for 3 months now met most of his friends esp the girl one only have a problem with the 1 girl, which she is married my boyfriend i guess use to go to her horse barn after work all the time when he was single to hang out with her which i guess her husband was there sometimes but all the time, i met her everything was fine she invited me over to hang out with the boyfriend i even helped her on her new land never said an out of a way word to her have always been nice to her! But now she doesn't invite "us" over just him she invites him over to ride, wings or just to hang out i understand they have been friends for a long time but... I confront him about it I just get i don't know so he asks her about it she says she doesn't have a problem with me likes me but then y does she not invite me over along with him anymore?

It's like I'm not allowed to have an opinion about it he says he wld take me with him but i feel unwelcomed i feel like my feeling dont matter he even texts her "hey i was just thinking about you i feel this is inappropriate on his part i dont think there is anything going on but dont i have a right to feel at ease? He tells her he cant hang with her now when we use to hang out with her all the time! I feel like he is not trying to make me a part of that relationship like he use to i dont know what changed

Am I jumping to conclusions? O and when he is texting her he gets all happy like saying she is funny. he doesnt think anything is wrong im jealous etc! any advice would be great!

thanks for reading!:)