Jealousy

So, even though we have a very casual relationship, I am finding myself jealous of the girl that he is out with right now. We have talked about this and neither one of us really wants anything serious. I even talked to the girl that he is out with right now, letting her know that she has nothing to worry about with him! I have known him for about a year or so and was vouching for his safety-ness, LOL. I am not the chick who is supposed to get attached like this. Honestly, what the hell is going on here? I am jealous of the time that he is spending with her. Even though, he is coming back here tonight. I am finding myself becoming very attached to him. I realized that the other night when I dreamed about him. I have not dreamed about guy since my ex. When he spends the night here (and he is the only guy I have ever let do that, except one) I enjoy the time that we spend together. I relish waking up with his arms wrapped around me. I even got mad at him last night for texting her while we were together! And I don't mean like a little mad, I mean a great big green-eyed monster welled up and I had to choke it back down! I finally told him that when we are together, that is my time, no one else's. I think that it is fair and I will do the same for him. I thought that I was over this stupid emotion, but apparently I still have a bit to learn. If I can't get over this feeling with a casual lover, how am I supposed to get over it with a permanent one? Am I just not meant to find love again? I know this is kinda sappy but I had to get it out of me. Thanks for listening. *smooches*