My bf and i saw his ex in the store today

My boyfriend and i have been together for over almost 5 months. On my end everything has been great but yesterday while out with him we ran into one of his ex’s. I know this is his ex because he’s showed me a phot of her before and after leaving the store i remembered who she was.

So at first it seemed like he wanted to avoid her. They eventually crossed paths and he said “hey” and she said hey and he went back to shop. My boyfriend and i had separate things to get so we were grocery shopping separately. She went down an aisle he was on and she started talking to him .. They started talking so i continued to do my shopping while they were talking. After a couple of minutes i glance over towards them and he started teasing her a little. My boyfriends ex was pushing her basket and he would grab the end of her basket then releases it and start laughing.


I went to the aisle nearest them and he was bringing up their old memories and their little inside jokes. He then told her randomly “you need a longer T-shirt “ she said “ why is there something on my butt?, is my underwear showing or something” she starts looking down . and he said “na“ and started smiling while kind of signaling to her butt size/they was her butt looked in the pants she had on. (he didn’t directly say her butt size/shape but i could see where he was going with what he was saying) He asked her about some job she had applied for and what was the status on it.
And basically they were joking on each other the entire time we were there. He asked her about her glasses and she said she wears contacts now and he said “oh you’re just trying to show off that face”. The whole time we were in the store he would randomly say things out of the ordinary to her to get her attention or say her name and just say something completely random that he could’ve kept to hisself. And right as she was leaving the store he walked behind her grabbed on her hair and yanked it...

Now i might be overreacting or reading too much into it but he obviously wanted her attention , i couldn’t believe how child like he was around her