Very brief background - been with boyfriend/partner for nearly 18 mths. He has a good female friend. Fine, met her a few times, nice girl, friendly to me, etc. He doesn't go out of his way to include me when he sees her. Always feels a bit awkward when the 3 of us are together. Have accepted/tolerated the friendship thus far despite reservations, they've previously slept together, long before we met apparently.
Few weeks ago they went away to a gig up north, with a couple of others, staying at another friends', about 8/9 in total. I wasn't invited but let it pass. Found out last weekend that him and her shared a room. Just them. He slept on floor, she slept on bed.
I am annoyed about this, he thinks I'm 'over reacting' and being 'silly'. Having the talk about it tonight so just looking for some quick reactions.
Conundrum is that I trust him (or did), I don't think he had sex with her. BUT i do not feel happy/comfortable with the closeness of their friendship - did they see each other half naked in the morning? Did they lie and chat the next morning?
Thanks in advance.