Weird situation

This guy I work with and I have had a weird relationship with one another. It started off great and I thought it may be the start of something new. The more I talked to him,the less I trusted him however. I was pretty sure that he just wanted sex from me,but there was a small part of me that thought MAYBE he wanted more. We got into a fight ands stopped talking for a little bit,I thought it was over..apparently,that wasn't the case. We kissed at work very passionately after we talked about our fight. I had another guy visit me at work and I was very surprised with how upset he got over it,I didn't think he'd care because he was so hot and cold. He kept asking me over to his house,but late at night which I found really weird and sketchy,I'd always decline and he seemed genuinely upset. He eventually stopped asking,so I thought I'd ask him to hang out. I ended up going over his house and it was normal and causal at first. We were cuddling and then we started making out. He was all over me and turned me on a lot. Of course,we ended up having sex. He was very nice to me after and even offered to cook me dinner. I left shortly after and we kissed. He acted totally normal and nice to me to my face and talked to me in person every chance he could. Two weeks went by and hadn't heard from him outside of work. I tested him to see if he would hang out with me again so I asked him in person if he would and he said yes. I texted him and he ignored me for a little bit,but then he basically said he didn't want me anymore. He said he didn't expect that to happen and now it's awkward. He also said he wasn't "that into me anymore" and it "wasn't what he expected". I knew I was used. He didn't know me very well and never tried to get to know me really, so he had no basis to even say that. He acted like we were something when it was really nothing in my eyes,he used me and he was lying about it claiming that he didn't use me. I respected his wishes and stopped talking to him and now he acts like he hates me. He avoids me at work at all costs and even told the boss on me for something I didn't do. He's the one that ended things,he has no reason to dislike me. Why is he being so weird and childish?

I would guess hes just a immature male what he did to you was so wrong on so many levels. It may be hard but i think your going to have to try and forget him, if it happens to interfere with work than you may have to talk to your boss about it. I'm sorry if this doesn't help.