I’m confused. He likes pics of other girl in a bikini and then lied. Not sure if I’m allowed to be upset.

So I (31F) have been dating for 5 months with this guy (28M) and we are exclusive.
Some time ago we had a conversation where he told me he never likes Pics of girls with not too much clothes on, that he is not like that…

The other day I was checking my friends suggestion list and I saw a girl he follows. I was curious so I entered to her profile and I saw he liked many of his pics, including pics in a bikini (a few from dates I have been with him). I felt a little hurt and insecure about it.

I told him about this as a joke. Like joking about how he lied and actually give likes to girls in bikini.
He denied he did that and he said his friend must have done it since this friend borrows his phone to check on his ex Instagram.
I didn’t believe him because it wasn’t just one Pic liked, but several from different days.

So I’m confused, I don’t wanna have a toxic attitude but I can’t help to feel insecure about this. The girl is so pretty, I think much prettier than I am (even if this guy always tells me how beautiful and sexy he thinks I am).
He actually becomes jealous when I post a Pic myself, he doesn’t likes it at all.

So, I’m not sure if I’m allowed to feel bad about it or I just have to open my mind to know a like doesn’t mean anything…