How to move on from a girl (25F) I (29M) dated?

It began right after the events of my last post while I was healing from a breakup of my almost 10 year old relationship where I was dumped by my ex (29F).

Me (29M) and my colleague (25F) had a crush on each other which I found later on when we started dating but at the time I didn't want to act on it, on my end, as I was not over my ex at that time. All this changed when she and I alongwith another mutual female friend of ours had plans for a Saturday. We somehow ended up at that friend's house with plans for dinner and drinks together, the three of us. That friend of ours fell asleep after a couple of drinks and some rounds of games. This is when me and her (my crush), let's call her B, got to talking. That's when both of us confessed of having a crush on each other. We ended up making out and sharing a lot of conversations over that night. It was magical and we both cherished that night a lot for the coming few weeks because that's when we found out that we both had feelings for each other and bonded over other things too.

We started dating each other and decided to take things slow as both of us were healing from past relationships. She had gotten dumped from a 1.5-2 year old past relationship and felt deeply about it so much so that she had to be hospitalized due to physical ailments like low BP and asthmatic attack after her breakup. It had been a year after that then.

We used to talk daily for hours and it really felt like I had finally found someone who I can trust and grow together with in the long term. Despite all of that I was conscious of having to take things slow because I didn't want this to be a rebound.

10 days or so into dating, she said that she loves me. I so wanted to say it back to her but I held myself back as I didn't want to rush it and hurt her and myself in the process. I told her this exactly and affirmed that I will say it back to you and once that happens I will mean it and won't ever stop saying it to you. Over the next couple of weeks she told me that she loves me multiple times. I really was feeling it for her too and eventually said it back to her. She had an emotional outburst and cried a lot hearing it from me as if it was the only thing she was waiting to hear for the longest time. We embraced and in that moment I felt everything was alright and it was the best thing to happen to me in a while.

We were going strong on the daily conversations and late night calls which would stretch for hours. Heck, we would sleep while on video call daily, talking to each other right until we fell asleep. It was magical like a teenage romance is what she said.

But things were going too good to be true I guess because a week later she decided that we should stop dating and part our ways. This was because according to her things were going too fast and if we continued to date we'd definitely end up in a relationship and she couldn't deal with another breakup after what happend the last time, is what she said. I tried to convince her that even I am aware of the situation and promised that I was in this for the long haul and that there was no hurry. We could take our time before being sure and taking any further steps. She dumped me regardless.

What followed were months of her acting distant and rude to me and making me feel unwanted altogether, stark opposite of what I had felt while we were dating.

This changed for a bit when we were on a trip together along with 3-4 friends. That's when we got intimate a couple of times and a few times after that, over a period of 1-2 months. Each time this happened she used to question what we were doing and said that it was wrong and shouldn't happen. But everytime we were alone we couldn't stay away from each other.

Then one fine day, very casually, she asked my opinion on what she should wear for a movie date with her ex. I was devastated. I couldn't understand how could she ask me something so diabolical so very casually. I knew that she was madly in love with her ex and was finding it hard to move on from him, to the point that she was ready to take him back if at all he ever returned. I was sure that I didn't want to go back to my ex from the beginning of the time we were dating but she always had that thought in her head. I even asked her during the time we were dating how could she love 2 people at the same time. She said that's because she knows her ex won't come back ever again and what she was feeling for me was real. I thought at the time that she was going through something very drastic and only time and love can heal it.

We had many fights after and she started acting very rude and cold after that. I too decided to keep my distance as I was hurting very badly. None of it made sense to me.

The last nail in the coffin was when she told me very casually one day that she had met someone online and they were seeing each other. I was heartbroken. The girl who made me feel so loved at a time was hurting me so bad now. That was 2 months ago.I have been doing bad ever since. Sleepless nights, overthinking, breathlessness, stabbing sensation in my heart have become common.

Got to know today from her that she broke up with the guy but then too she spoke highly of him. At the same time she said she doesn't want any serious relationship with anyone because she feels she is not meant to be in one and that even friendships suffocate her at times.

Meanwhile I still have feelings for her but I also hate the fact that I can't move on from her after all the things she said and did.

I have tried to focus my attention to other things in life but I just don't know why I keep having these thoughts and feelings and they are too intense to ignore. How do I really move on from her ?

TL;DR:

Got dumped from a 10-year relationship and shortly after started dating a colleague who I had mutual feelings for. Things escalated quickly, intense connection, daily calls, she said “I love you” early, I eventually said it back. A week later she ended things saying it was moving too fast and she couldn’t handle another breakup.

After that she was hot and cold, we were intimate a few times but she kept saying it was wrong. She was still in love with her ex and later even asked my opinion on what to wear for a movie date with him. Eventually she started seeing someone else. They broke up recently, but she says she doesn’t think she’s meant for relationships and feels suffocated by them.

I still have feelings for her despite how much this hurt. I’m dealing with anxiety, sleeplessness, and constant overthinking. How do I actually move on?