I started a new job 2 months ago, and I met a guy there, who was also new (we're a group of 4 new employees). He immediately started to pay a bit more attention to me than the others in the group, he was a flirty, touchy. He wanted to team with me everytime we had to, especially if the workshop included physical contact. But he was charming and gentle, we seemed to have a nice "connection".
After a few weeks, he asked me out, suggesting that we went out just the two of us for a drink one evening. We did, and at several moments I felt like he wanted to get physically closer. When saying goodbye there was an awkward silence and when he kissed me goodbye (on the cheeks), he kissed me quite close to the mouth. But he didn't reach at me much after that, which led me to become a bit colder (he did reach at me 2 days after the "date", but to ask help for sth, and didn't even mention that evening). I was confused.
He started to blow hot and cold. Sometimes he is agressive to me, or distant, other times he still is very flirty and touchy, makes a lot of blunt sexual or romantic insinuations. When we do sth just the two of us, he says things like "we're doing it as a couple" "I'm glad I can have a romantic walk with you"... He also compliments me (my eyes for instance). Most of the time, he'd also look at me when I'm not looking.
Because of his behaviour with me, I assumed he was single. I found out a few weeks ago that he had a girlfriend, he casually mentionned it in the middle of a group conversation. I was bummed. And even after saying that, he kept hitting on me...
He also started being very moody and agressive with me. I confronted him with that, cause it was making me incomfortable. He said that he really appreciated me a lot, that he could be sensitive and moody when he takes a "close interest" in someone. I didn't know what to think of it.
I don't want to have anything to do with him anymore, I felt so confused and deceived when I found he had a gf. But he is being super cold and rude to me again, it's becoming a bit of a problem in our group of friends. He ignores me even if I'm sitting next to him, but he is super outgoing with everybody else. He doesn't speak to me. If we're having lunch for instance and he's serving water, he's gonna offer it to everyone except from me. And he acts very rude generally and despising towards me. We have lunches and coffee breaks with a few friends/colleagues every day. If I'm asking who's available to join me for lunch, and he is up for it, if he realizes the others can't make it he changes his mind at the last minute and ditches me in front of everyone saying he'd rather have other plans then. And he never apologizes for ditching me.
I do not know what to do or how to handle this situation. The atmosphere is tensed, but I don't want to be rude to him cause it may backfire. But I just can't stand his attitude anymore, I don't understand this change. We seemed to get along and have a connection, I thought he was into me at first. Any opinion would be appreciated !