aio or does this seem weird?

my boyfriend (21M) and i (20F) have been together for about 5 year and we also have a 1 year old together, now we have had some troubles during our relationship( not super bad,) but he messaged his co-worker(20F) these messages and i just have a weird feeling about it. some backstory is that he used to flirt with me by texting me “heyy loser” as well so i just need to know if im overreacting or not lol, thanks :))