Need To Vent and Need An Ear

Ok so after crying a little and thinking, I decided to write about this and get it all out of my system for good. I hope...
Anyways, I was "seeing" this guy who I work with. I knew what how things were going to be between us from the start. Its was casual and that was it. And I was perfectly fine with that (or so I thought until now). I didnt care if he saw other people as long as he wasnt serious with some already (i refuse to be the other women and dont want to come between anyone and the bf cuz I wouldnt want that to happen to me ya know.) Besides I was "seeing" someone else too. People at work starting questioning what was going on between him and another co-worker. She said nothing was going on and that was that. I had my suspicions too, but didnt say anything about it, cuz I thought maybe they were just becoming good friends. That is until I found out little things that just didnt make sense. But whatever, we were still seeing each other.
The rumors kept going on, and whenever we were together he wasnt acting the way someone would in certain moments. I felt something wasnt right from the beginning but said whatever. So anywho, I decided to ask him myself if anything was going on. I told him that I needed to talk to him and that he might not like what I was going to ask him, but I didnt know if I should do it right then and there. He told me to ask because quote, "You may not have a chance to do it later". I know that he didnt mean I might not see you later but something else. What the He!! is that suppose to mean? He said it twice. I have a feeling he knew what was coming. So I started to ask the question and all I got to was, "Are you seeing H..", when he opened the office door and walked out on me. BUT he was smiling at me as he left and as he walked by the office window???. Then I had to go into another office that he was in and he pretty much looked at me and bolted in the other direction.
When I came into work today he just looked and didnt say anything to me and I was on the silent side to. I know that he called the area that I was in (the "other" female works on my side) and when I answered the phone and said this is so and so speaking, he hung up on me. And they left together after we all got off work. It doesnt help that a co-worker used me as an excuse to work in m area and not the one he was in, stating that she wanted to trade sides with me tonight, because I quote," Don't feel comfortable working wirh the "other" female". Which was complete BS, and he was in the office and supposedly wasnt happy to hear that. Fortuate for me another co-worker who knows what is going on told the other workers that, that was complete BS. Which is true I have nothing against the "other" female, except that she doesnt do shit on the job. Our whole team complains about that though.
So when they left together and I am sure she made sure that I overheard they were leaving together, I started to ball.
My thing is, ok so yeah, I guess I did start to get feelings for him, but I seriously and honestly did know that we werent serious at all from the begining and I was honestly fine with that. I know most of my feelings started to come when I kept noticing them talking all the time and hearing people say this and that about them. But mostly, 95% of me just wanted him to be real and honest with me. I asked the question, not from jealously, but honestly because if they were getting serious with each other, then I wanted us to stop. Especially before I started to get some real feelings from him and have it be uneasy for him and me. I was never gonna be like, well its either her or me and it better be me. NEVER.
You know, I was mosre baffled, confused and mad that he walked out of the office on me, then if he had of said yeah we are seeing each other. Like I said I knew we were friends with benefits from the begining and truthfully its what I wanted. Not anything more.
My questions are..
1) why couldnt he just be honest with me about everything. ok so in some ways if we are just friends with benefits, then its none of my business who he sees. But him just walking out like that and doing what seems to be sneaky stuff, makes it seem like he was trying to hide something from me.
2) If I was just a friend with beneifts, why the heck did I need to be questioned about where I was going out to one night? And then when I ask, "why" he gets hyper and asks, why did I need to ask why. Its not like I was going to show up where you were. OK, SO WHY DO YOU WANT TO KNOW THEN?!?!? (Everyone I told this too (my friends) said that he wanted to know cuz he cared about what I was doing)
3) What is it with me. Why am I always the girl who is "one of the guys" and like a lil sister OR the opposite extreme, just someone guys want to try to make out with or TRY to sleep with. And I can count everyone who I have done anything with on one hand maybe less. So I am definately not a slut. I always have people (and I am NOT trying to be concieted, I am just stating what people say) tell me that I have so many pros going for me, and that any guy would be lucky to snag me, your too good/nice for them to treat you like this, blah blah blah. So why am I always getting the shaft it seems?
The thing is I think I am more pissed off at myself in this whole thing. I said no to him for about 2 months before I finally said yes to seeing him. I should have kept saying no. Plus I knew what role I played from the beginning and I let myself get emotional. I have always been the one my friends generally ask for advice on what to do in relationships, even though I have never had the bf. With this situation I didnt even take my own advice and didnt follow my gut. Which is something I always do. STUPID ME Now I dread going to work this afternoon. My friends say, that he isnt worth me going through this, he sucks, I can do better, yada yada. I know this is true and partly my fault for getting emotional, but I have to admitt it still hurts. I have NEVER cried over a guy before until now. First time for everything I guess. I will just go to work and start new and try not to think about it. Hopefully a good boy will come along and make me forget about guy
OK, writing this did make me feel a lot better. I know this might not have been "appropriate" to write, but I just needed to get it out. I more then understand if it needs to be deleted, but if anyone has any advice or a hug, I need it . PM or post it! I have enough drama in my life from my friends, I dont need to give myself more to deal with

Ohh BTW, the other guy I was seeing was dropped way before I started getting feelings before guy. We just didnt really clique anymore.