Seriously guys, thank you, all of you, for the insight. I may not agree with everyone but I really do appreciate the perspective. I feel like I should compose some more responses to the posts that have been made... But I can't at this moment.. Because I am dealing with a new development that I really didn't see coming and I'm sad, hurt, and having trouble coping.
So I should say that in addition to the information that I've given in regards to our work situation, it may be relevant to know that we work the night shift (11pm-7am).
After reading this thread together and discussing it, I was feeling a hell of a lot better about it. I was still a bit uneasy, but I was about ready to say yeah, I am truly okay with this. Part of it is because I know that indeed, he doesn't really have a lot of other opportunities besides Thursday nights to see her. And yes, since I'm at work it technically doesn't take time away from me, even though as it was pointed out, I am used to him texting with me so it kind of is. BUT I had reconciled myself with that fact.
All Thursday morning after work, I was asking if he had talked to her, and he said he hadn't and that they probably weren't going to hang out. I came into the room to go to sleep and his phone was on the floor and lit up, so I picked it up and put it on the table, and I saw the conversation open was with the other girl (I will call her J), and I didn't read it, I just asked him what they were talking about. He said he texted her saying he wouldn't be able to hang out because he has a pimple (his attempt at a joke?). And I knew she replied but I didn't ask about it, and he didn't say anything about it either.
Then we went to sleep. He woke up before I did and went to go make up some food for me to take to work. He woke me up before I needed to be awake, and as I was telling him to let me sleep for the extra half hour, he said he was leaving to go pick her up. I was a little weirded out, but I was sleepy and just asked what they were going to do. He said they were just going to go out to eat. He could tell I wasn't real happy, so he reassured me that he would keep to the boundaries I had set in the first place, before ANY of this happened. The boundaries were that he would have her home early (2 am at the latest, because the first time he was up all night with her until 6 am and then he was shitty the next day to me because he had no sleep. So that's the compromise) and that they wouldn't be in our bedroom or in our bed. So he left, and I wasn't able to go back to sleep since he woke me up with that delightful news, so I got up and went to work. He texted me at about 12:30 saying he was taking her home. I texted back asking what they did. He said they had two beers at a bar and then went back to our place and "got a little naughty." So I called him, wanting to know details. I am the type of person that needs to know details so I don't make things up in my imagination, and he knows this because I have specifically told him so. I had to prod him for details. He finally told me they had sex, which in itself actually didn't bother me too much because I figured that would happen. But then I asked where they did it, and he said, "in the bed, but I'm washing the sheets!"
I am devastated and furious and hurt. I made it clear to him that our bed was OUR bed and if we had a threesome in it together, that's one thing, but I don't feel comfortable with him having sex with her or anyone else without me there. And I've agreed to the same, I won't have sex with anyone else in our bed either. When he had woken me up, he had said, "don't worry, we won't even come in here." And when I was talking to him on the phone hearing about what happened, I asked him why he thought that was okay. He said that because when he said it, I didn't really respond. I WAS ASLEEP. I told him that he knew that was the deal, and he didn't need me to reaffirm it. Also, I don't know for sure, but the way things went down, I think that he asked her to hang out, even though he had told me that he didn't think they would. I feel so awful now. I had trusted him so incredibly much, and now its been shattered. This is a huge step backwards. I might have to tell him that we need to close our relationship for a while.
I've tried to look on the links to threads worth reading and the other resources on this site, but I can't seem to find any the specifically deal with how to handle when your partner crosses a boundary. I don't even want to go home this morning (I get off in 2 hours) but I have nowhere else to go. He's going to be sleeping like a baby when I get home and I'm going to want to clock him. Just kidding. Maybe.
He knew the rules! And also I texted her telling her that there was an issue, and he had not even told her that this was part of the negotiation. I thought this man was such an honest, trustworthy person that actually cared about my feelings and was able to suspend the "thinking with the dick" in order to preserve the awesome thing he has going with ME... But I'm so lost now.
If someone can try to give me insight into not thinking he's a complete fucking monster douchebag, helping me see his side, or helping me cope with this, I will be eternally grateful.