Hi Rich & welcome
I agree with BLR.
The new boyfriend may be a bit controlling, or it may just be that they want to please each other and know where the other one is all the time because of closeness and the intensity of a new relationship.
You said something very telling:
'I would like to be good friends with her like we were a while back and maybe more.'I'm guessing that the girl knows about the 'and maybe more' bit.
Her boyfriend might have noticed, too.
You see, you are saying that you want friendship ~ but 'maybe' you actually want 'more' than friendship.
And maybe, as she now has a boyfriend, she is wary of this.
She may be trying to let you down gently by constantly referring to her boyfriend ~ so that you get the message that she is now taken.
You can certainly ask her, or them, to join in group activities, but don't be surprised, or upset, if she declines, or if she arrives, but appears to be very close to the other boy.
Take care
