Search Results: checking out other girls

I've had guys that I've spoken to and that I'm on good terms with suddenly begin flirting with me by making rather sexual remarks. There was a guy in my dance class that made it rather obvious that he was checking me out while I was stretching by saying "mm hm" while smiling and I asked him what that meant and he said "your body"... yeah... and then he just started up a rather pleasant conversation with me (so that made me think he was joking around earlier) but I think guys flirt as a joke (at least I know that girls do) and I thought that guy was gay until (I think) I caught him checking me out a couple of other times. So do you guys flirt with girls as a joke? I'm asking because I don't want a relationship and since week 2 of my cycle is coming up and I'm going to be really sweaty in that dance class my pheromones will be all over the place. Should I be worried about him or not? I wouldn't mind being friends, but I don't want him thinking of me like that (at least for now because who knows?) what do you think?

First off... me and my boyfriend been togeth for over a year
I had a bad previous relationship which ended 3 years ago
But i still have some trust issues
So i dont fully 100% trust my boyfriend
Over the course of our relationship, he has given me his passwords to his devices (phone, computer, etc)
I was checking his phone the other day and he was searching up girls on his fb and instagram (girls that he knows.. from work, from his high school, from primary school)
But he doesn't talk to any girls.. only the ladies at his workplace (he works in nursing home so majority working are old nurses and middle aged nurses but there are few young girls too)
Im not sure why he did this?
But i was quite jealous and got abit mad so i confronted him about it
Our conversation:
Me - so i know you're talking and searching up girls?
Him - yeh i talk to girls from work only and its all work related
Me - why u searching girls up? I saw your fb and instagram
Him - i dont just search girls up. I search guys up too. Wth?
Me - so u wanna be with those girls u searched up?
Him - what u talking about? I cbf talking about this. I did nothing wrong. Think whatever u want babe.
Me - yeah you're searching up and looking at their photos and all that
Him - think whatever you want. Im not doing anything wrong. I know im not doing anything wrong. I know what i do. Im not cheating on you. You even know all my passwords. Stop being insecure. Are u trying to argue with me like u always do? I can't be bothered arguing right now.
Me - and you liking and commenting girls pictures (*im lying about this by the way.. just wanna see reaction*)
Him - um no i dont. I know if i do, you will go psycho on me like u did before. And i had to spend hours to calm you down. Yea dont have time for that shit so not going to do it.
He was talking to me throughout in a calm tone
Wtf?
Does he seem genuine about it?