Confused & crushed :/

Im confused and upset over a recent friendship/relationship breakup/deterioration. To try to put it concisely: I met and immediately developed a crush on someone last March and it was one of the most powerful feelings Ive had in ages. I didnt stalk him online to find out more about his life, because I didnt want to be creepy and I thought maybe the less I know, the better. (It was a messed up way of trying to not get too invested & I guess a way of self-preservation.)

We started talking on fb messenger and he seemed like a nice person and we had incredible amounts of things in common. Movies, fashion, furniture, you name it and we had the same tastes in it. We talked about personal things and usually spoke for hours every day. Some messages got flirty and eventually we also talked about sexual preferences and fantasies, something I have never discussed even with previous boyfriends. The messages about fantasies got very explicit and would often be about things he wanted to know about me (would I enjoy certain acts etc etc).

We worked together on a project so until the end of July I tried to be quite professional (the dirty messages didnt start until later), and in person neither of us have ever been flirty with each other though weve met and hung out several times.

Over a period of seven months he sent me a million selfies (nothing naughty, just nice photos of him, but I genuinely mustve gotten a few hundred) and I sent him photos of myself as well, wed often exchange compliments about our looks, fashion choices and so on. He has also told me I look hot and or cute/pretty.

All this time I was nervous and confused, not knowing what was happening, if he liked me or not. I found out last week that he has a girlfriend and it crushed me. In seven months of talking to me sometimes for 5+ hours a day, he has never brought her up even to say Im having dinner with my gf tonight.

I will admit I shouldve checked, it does say on his fb profile that he is in a relationship and now Im not sure if I did check & didnt notice, or if it hasnt said that the whole time weve been talking or what on earth happened.

I told him I feel like a fool, like Ive been played around with. He said he was sorry, but also said he noticed I had a crush on him but hoped it would pass. And still didnt think he shouldve mentioned the girlfriend...

I spent three days feeling sick to my stomach over this, blaming myself for how stupid Ive been and how blinded I was by my crush, even though Ive known for a long time that we wouldnt make a good couple. I dont know if I can forgive him for not being upfront with me & I feel like all this time hes taken advantage of me and used me as just an ego boost. I feel sad because Ive never met anyone I have this much in common with and tbh anyone Ive been this attracted or interested in! For reference we are in our mid to late 20s. I have a history of depression, anxiety and low self-esteem which he is aware of, he has suffered with some degree of similar issues recently.

Im struggling with processing this: how do get over this and can I ever trust him with anything? Can I be friends with someone who thinks its okay to talk to other women about intimate things even though hes with someone else (I dont think thats acceptable in a relationship and certainly not in the way he spoke to me)? Is there anything worth saving?