How to move on and let go of my Avoidant ex who's seeing his neighbour now?

Long story short...dated a guy from under 3 months who pursued me at the start of July.

I really felt like we connected, we could talk for hours, I was so attracted to him (not just physically) and I thought I finally met a secure healthy man after being hurt and rejected by lots of guys (I'm 32F he's 37).

About 2 months of dating he mentioned he's having doubts, and how he's had doubts with every girl he dated. The longest relationship was 8 years that ended back in Covid due to his ex partner emotionally cheated on him.

We agree to still try and about a month after the doubt talk, we coincidentally run into his last ex (that he hasnt seen for over 10 months) and hours later decided to break up with me.

I was/am devastated. Two weeks later we met up...and met up again 2 weeks after that (he wished me a happy bday in between).

Understanding that would be our last time that we meet for a while, I believed him when he said he doesn't have the emotional capacity to date, how he needs to heal, and he doesn't even want to consider dating. I believed him. Especially since he's trying to start a new business which hasn't been going well and taking up a lot of his time.

So a week after our last hang out...I noticed he reposted a story of him in the middle with a girl being awfully close to him. I took it has a hint to move on so I unfollowed him and try to heal.

That night (which was 4 weeks ago now) he called me out of the blue. I'm thinking maybe he wants to work it out with me? Well the first thing he asked when I picked up was if I blocked him, which I said no but I did unfollow him for my wellbeing. Then he said the reason he called is because he felt like I'm keeping the door open for him and he cares about me, to tell me he's seeing someone already. Not even 5 days after we met up. I asked who and he proceeds to tell me it's his next door neighbour.

I was an emotional wreck during our facetime. After a month I'm still not doing okay...I recently found out she's a doctor and she seems like a nice person. I know I'm a great person but I can't help but feel less than...can't stop comparing myself. Like not even days later you tell me you're seeing your neighbour? Who's a doctor? I know she's a rebound (he moved into this place after we broke up) and he's clearly an avoidant...it just hurts too much. He believes once he meets a person he juts KNOWS to be secure with. His words is "if it's not a hell yes it's a hell no".

Then the kicker is find out my job contract (a job I love doing) isnt' extending me next year so I just really feel down on my luck. I guess I'm sharing this for guidance and help...because I don't know what to do. I cant shut my brain off...like did I mean anything to him? It hurts too much.

For those who have had similar situations like me and thought they could never get over someone they fell in love with and their avoidant ex moving on...how did you finally fully get over someone you never thought you could? I just want to thrive already...