Weird feeling about boyfriend and our friends partner?

my boyfriend (J )& i use to date, decided to be friends, & now in a relationship, also have a child. We met through a mutual friend (H), we share the same friend group. While being friends, another girl (A) started dating someone (R). They’re gay.. Although both have dated men. J would say things about R, how she is attractive.. would suggest things like “i say we all take our swimsuit tops off” while being at lake/pools. (At this point we had been intimate before so he’s seen me topless & had expressed no attraction towards A, as she is more masculine than R) He would also hint things that are straight up inappropriate to say to your friend’s (A) significant other. Neither A or R said anything to him.. they’d just laugh it off. During pregnancy, J wouldn’t make eye contact with R or look her direction.. when we would hang as a group , we’d say bye as a couple, & J would go back to give a hug to R/A. I questioned why he would & he’d get defensive resulting in a screaming match. Every time A would mention R would be coming or showing up later when we would hangout, J would suggest to leave a little after. I picked up on this but never said much.. im more of a watcher/mental note taker. R also didn’t attend our baby shower with A & stopped coming around all together when i had the baby. 
months pass it’s Js birthday… R decides to come, she never comes with A they always come in separate cars. (birthday takes place at our home). J is starting to drink much.. results to him being very friendly. He offers R drinks/shots, i didn’t see when the conversation started, i walked up when he was trying to get her to drink with him.. when i did, i got a feeling they had been caught almost.. she made eye contact with me immediately & had said something along the lines of “ (my name) J is trying to take shots with “us” but we aren’t drinking” & kind of forced a laugh..
He turned to me & said since it’s his bday he wanted to have a drink with everyone. I didn’t say anything. 1/2

Updates
12 d
Will put more when someone comments
Updates
12 d
I didn’t say anything, just gave him a look.
she continues to not come around anymore. J also mentions not to invite A around anymore, assuming bc she’ll bring R.
We plan to have a get together at H’s house to celebrate A’s bday with mine since it’s close. i mention to J that when we say bye to the group… we’re doing it as a family not going back for a second round & giving certain people hugs. Also said I dont plan to drink since we’ll be bringing baby & i hope he plans to do the same not only
Weird feeling about boyfriend and our friends partner?
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