Why does it bother me so much that my boyfriend talks with his Ex’s?

Yesterday I was in messenger chatting with my “half lemon” and suddenly he tells me that a “friend” is asking him things about me, how our relationship was going and things like that. At that moment I felt an electric pulse running through my back all the way up to my neck, could almost felt the steam coming out of my ears, why the fuck is he asking things about us?!

That person is not really an Ex, he was a “sexual partner” that he had some time ago, and for me, “fuck friends” are way more threatening than Ex’s. With an Ex there is a sentimental history, a past that most of the time is painful to remember, therefore one tends to avoid any contact with that person. But with a "fuck friend" things are different, you only remember the lust that you felt for that person, and even though my boyfriend tells me that he loves me, sometimes lust is stronger than love. And don’t get me wrong, I am not saying that he is cheating on me or anything like that (he spends most of his free time with me…, or so I think, therefore he don’t have the time to spend with someone else.), besides, I trust him, but is just that I feel uneasy around that person, it bothers me that he is inquiring things about our relationship, but what bothers me the most is that my cute boyfriend, instead of telling him to fuck off, that we have a steady and solid relationship and that what happens between us is not his problem, he just went “invisible” to ignore him…

Am I acting like an insecure person?

Probably. But I bet that if I had one of my “fuck friends” in messenger, or his phone number stored in my cell phone, and communicate with him regularly, or let him call me at wee hours, he sure would be pissed off, maybe I should do it to show him how it fells…