My partner and I have been together about a year and a half. We have been living apart the past few months because he needed to work and I had to go home to see family because my dad died. I came to his hometown a couple weeks ago to stay with family over Christmas & NY.

Today he said he wanted to see a person he'd been seeing while we were apart and expressed it as "because she's a friend and I want to see her before I go, and I haven't because you've been back". He invited me to come meet her and I said I would be open but then later he messaged that she was tired and wasn't up for meeting me and he'd just stop by on the way home after he finishes working. He gets back a bit later than expected and when I ask how she was he didn't express much but seemed a little off.

I am aware they've had a sexual relationship while I wasn't here but not seen each other a lot. He fell asleep on the couch and I checked his phone (I know this is unhealthy behaviour and feel really shitty about it) and put together they had had sex when he went by. I woke him up and asked and he was honest but I asked why he hasn't told me that was what he was doing and made out he just wanted to say bye because they're friends.

I am aware I'm being somewhat irrational here but I have expressed previously in our relationship that I want clear communication and to be kept in the loop. He responded "I'm not going to tell you every time I have sex with someone"... I'm not sure what exactly I want but I am feeling weird about things and on top of my grief and having expressed that my grief is bringing up feelings of abandonment and it's hard... I'm feeling like he's just doing whatever he wants without regarding my feelings at all.

I don't even really know what I'm asking. It's like 3am and having trouble sleeping so just feeling like I needed to write...