<human>: Ok, before the answer is *Obviously, yes* let me explain. 

Some time ago I add this friend of a friend on Facebook. He writes cool stuff, but we never talk much. One day he decided to actually come and talk to me and then in the first days we became friends. And more and more intimate with each passing day, which resulted in a fast connection. We used to talk for a long time every day because he lives in a state next to mine, but I planned to travel to see him soon. I've always had problems with attachment and I was happy to finally be able to begin to connect with someone again. Everything looked apparently perfect (or almost).

He had told me about a longterm relationship he was over with a very jealous and obsessive girlfriend, which for a long time didn't accept the breakup. He stated that they were still friends - *what I found very strange.*

One day I found her profile by his likes and I saw several things that indicated that they are still together (photos that he took, comments from his relatives, etc). I'm not exactly monogamous, I've had several open relationships and I wouldn't mind if he hang out with someone. The big problem is that he **believes** in monogamy and that he isn't seeing "anyone else" but his obsessive ex-girlfriend, which I doubt from the bottom of my heart that is just a friend. It hurts a lot because he's not being truthful with me nor with his own romantic options/lifestyle.

What should I do? Should I confront him even though we don't have anything serious?

Condense the text into a few key points
<bot>: found that my SO might be dating his ex but in doubt what to do because we don't have a serious relationship.