Questions: Guy's Behavior

Everytime i show/tell people what this guy did they dont understand and are confused why they would behave like this

So i dont know if those who have read my previous msgs or not, but we go to play cards, he stroked my hand one night then the next month id seen him he was ataring and at one point pointed his hands together towards me with his mouth open whilst holding eye contact

Would u class this as flirting? Please be honest and dont just say yes if u feel its being nice, my mum keeps saying this is the only reason why people are agreeing with me!

If youve seen this q before no need to comment, just vote. Thanks!

A guy I've gotten to know and I often engage in a lot of banter.
We have the same sense of humor, so we often call one another ugly names and then laugh our asses off.
He calls me Quasimodo, I call him Dickhead. It's something we thoroughly enjoy.
We don't hang out outside of our mutual community, but we do often spend time together when we're there.
Recently I joked about his behaviour to which he replied "but you still love me" then waited for my reply. I pinched my fingers together a eventually said "just a tiny bit, but only if it's mutual," he replied by pinching his fingers like I did and said "just a tiny bit". Give two playful punches in my belly and walked away.
I jokingly exclaimed "Hey, my baby!" To which he replied "Doesn't it sit on your backside?" Referring to my ass. I laughed along and said it was a conjoined twin, and the two of us kept joking about my "twins" for a minute before I left.
We have interactions like this more often than not, which is why I thought he might be interested. However, I just now learned he is in a relationship with someone.
Is this kind of behaviour normal when you're in a relationship or would you consider it (emotional) cheating or whatever term you'd use?