Hi
I'm not sure if I'm being too sensitive and overreacting.
I've been with my partner for about a year and a half. Things are good- we have the odd fights etc verbal but normal and things are going well.
Hes started a uni course in Septemer (he's 35 and I'm 34) and he's made friends with a female girl around 20 something in the course. The girl is engaged and getting married. They text every few days about stuff they're doing and uni things- she helps him out with writing essays etc.
The other say she messaged him talking about going to the gym and not wanting to at 6am and said she's chubby.
She then sent him two photos. One of her looking really slim in a bikini and another of her now (she's like a size 10/12) with a very low cut top. Both photos my partner made a comment and said something along the lines that 'he'd have abit of that' to the first one and a similar comment that he'd still have abit of that to her current photo. She responded with smile heart emoji and called him a cutie and she said shes not good looking and he said something like beauty is the eyes of the beholder etc. He then said something like are you my uni wife now aswell as my bestie. A day or so later he messaged her saying 'hi wife.'
I feel a tad upset over this. He says it's just harmless banter but I would never talk to another guy like thay albeit a friend.
He thinks I'm overreacting he loves me and it is literally just banter.
Please any thoughts? Perspective?