<human>: Give me the gist of the text in a nutshell

Me (24f) and my boyfriend (30m) have been together for 7 months now. We met through a dating site. I know I wasn't the only girl from there that he met in real life.

What I didn't know was the fact that in the beginning of our relationship, around 2 months in, he met with her behind my back, meaning not telling me about it.

We had discussed before this meeting took place that we were exclusive. The particular day I was meeting my friend, a male, and I informed my SO of the fact. Saying that, I was hoping that if the situation was reversed (him meeting with a female friend), he would tell me also. 

I would be totally ok with the meeting, but just the fact that it was kept in secret and that the girl was the other one from the dating site... well, make things a bit different and now I'm confused.

I have no idea if they have met again after that, because now I know that he wouldn't tell me even if they did.

Is it worth to bring it up after 5 months? How do I approach it?
<bot>: Bf met with a girl he met on a dating site without telling me about it. Is it worth to bring it up after a long time? Should I be worried?