Hi all, I am not quite sure why I am posting this here but I guess I hope that talking to other posters with experience in recovering from abusive people would help me, so here we go. Warning, long post ahead!
I was involved for a few months with a toxic man and I am now really struggling to forget and move on. He is a colleague of mine in a very senior position of power, while I am entry-level. He is not my direct manager but he is the head of a whole department in my company. He is 20 years older than me and divorced without kids.
With the benefit of hindsight, all the textbook red flags of abusive men were there from the very beginning: major love bombing, subsequent withdrawal of attention/affection, major future faking, compulsive lying, pushing my boundaries further and further, bullying me to agree to sexual practices I was not comfortable with, putting me in outrageous and humiliating situations, belittling me in front of others ("but I was just joking sweetie!"), refusing to take any responsibilities for his wrongdoings and so on. I also came to realize he is a functioning alcoholic as he is drunk every single night. I am not a psychologist so I am not qualified to diagnose what his problem might be, but there is definitely something seriously wrong with him.
He chased me really hard in and outside of the office until I gave in and started dating him, only to find out a couple of months later that he was already dating a religious girl barely out of school just for the thrill of taking her virginity away. He was of course feeding her a pack of lies about their bright future together. Once I found that out I realize that he wasn't just a fuckboy as I previously thought, he was sick. So I started pulling away from him while he did his best to keep reeling me back in. It took another two months on/off until I was able to break away from him for good. We have not been in touch since the end of May, besides short work-related communications.
I knew he was "bad" when I started seeing him, but coming out of an unfulfilling LTR I was attracted to the excitement and the adrenaline and I thought that it was just going to be a casual and transgressive experience. I thought I could handle it without consequences.
However, it has been two months since I stopped seeing him and I am really struggling with the aftermath of being involved with such an abusive person. I don't feel (and never felt) any feelings of love for him and in fact I think he is a disgusting person. However this experience with him left me feeling worthless, unattractive and boring. My previously very healthy self-esteem is in tatters. When he ignores me at the office, it feels like I didn't exist anymore. I irrationally crave his attention, even though I know it would be terrible for me to start seeing him again. I became unhealthily obsessed with this poor other girl he was abusing and keep comparing myself to her in a demeaning way.
I just don't understand why it is taking me so long to move on. This does not make any sense! He is a horrible human being I should only feel sorry for, and instead I am still (secretly) allowing him such a power over me. As I previously said, I never had issues with my self-esteem so this for me is a whole new experience. I even thought I should consider talking to a professional about this, but then I feel like I am overreacting because surely shagging a dickhead for a few months should not throw me in such a dark place?
Does anyone have any experience with this? Any suggestions? I just want to forget and move on for good 
(Before anyone points that out, I now know becoming involved with someone from work was a bad idea. I learned my lesson and that is not the point of my thread)