"work girlfriend"

my SO I recently caught talking to a co-worker from work. she refers to him as her " work boyfriend" which only made me want to beat her ass. she fully knows about him being with me, our 1 year old son and expecting a new child in 4 months. he swears it was all "emotional" not physically doing anything so it's not cheating, just flirting and "fun"at work he claims she talks to a lot of his co-workers this way. well to me she's a fucking whore and he's a cheating yes, THAT'S CHEATING in my eyes. because I'm not too sure how he'd feel if I had a little "work boyfriend"whom I called babe and gave hugs too daily. I would expect this behavior from a teenager but he's 26. And knows what i see as cheating in my own definition. 😌😌😌😌😌 anybody wanna disagree with me I'd really love to know if I'm even "wrong"for wanting to completely leave his ass

EDIT: not shaming women who have kids by multiple partners, but this chick has 3 kids from 3 different men so she should have a little more respect for mothers but, she doesn't. and as for him I'm pretty sure This relationship is over. No excuses.