Update: My avoidant ex appears to be reconnecting with the woman I worried about during our relationship, and I’m struggling not to spiral

I posted here previously about the end of my relationship with my ex. We were friends for about 8 years before dating and were together for around a year and a half.

We have only been broken up for about a month.
The breakup happened during one of the hardest periods of my life. My mother died less than two months ago, I had to leave her home, find housing for myself and my son, and essentially rebuild my life while grieving.

Now, only about a month after our relationship ended, it appears that my ex may already be reconnecting with a woman who was a source of insecurity and mistrust during our relationship.

The speed of everything is part of what is making this so difficult for me to process.

Throughout our relationship, one of my biggest struggles was feeling like I was asking my ex to prioritize our relationship and become a consistent part of the life I was trying to build with my son.

He wasn’t an entirely bad partner. There were good times. He did things for me, helped me financially at times, took trips with me, and could be loving and supportive. That’s part of what makes this so difficult.

But I also frequently felt lonely inside the relationship.
Sports, drinking, friends, trips, and his own plans often seemed to come before spending intentional time with me and my son. When I expressed that I needed more support, consistency, or partnership, I often felt like my needs were overwhelming to him.

Eventually, after another situation where I felt abandoned emotionally, I left, blocked him, and stopped sharing my location. He ended the relationship shortly afterward.

Now there has been a new development that has completely reopened the wound.

Before we dated, there was a woman he had slept with and talked about potentially becoming a stepfather figure to her child. During our relationship, she continued contacting him. He responded to her messages and deleted conversations between them.
This caused problems between us because I never knew exactly what was being said.

At one point, he blocked her.
Now that we have broken up, he has unfollowed me and appears to have reconnected with her. She has been posting things about falling in love, and based on the timing and other things I’ve noticed, I strongly suspect they are seeing each other again.

I know I don’t have definitive proof of exactly what their relationship is, and I know checking social media is making my anxiety worse.

But I am devastated.

What I can’t stop thinking about is: what if he becomes everything I begged him to be for someone else?

She is also a single mother.
What if he becomes involved with her child, prioritizes spending time with them, settles down, drinks less, communicates better, and gives her the consistency I spent our relationship asking for?

How does someone go from a year-and-a-half relationship with someone they knew for eight years to potentially reconnecting with someone else almost immediately?

Was he emotionally detached from me long before the relationship ended?

Is this common with avoidant partners after a breakup? Do they initially feel relief, distract themselves with someone new, and process the loss later?

Or do some people genuinely move on this quickly and never look back?

I also recognize that part of my obsession with whether he will come back is probably because I want reassurance that I mattered to him.
I want him to realize what he lost.
I want him to miss me.

And if I’m being completely transparent, a part of me still wants him to come back and become the partner I needed him to be.

But another part of me wonders whether I escaped a relationship where I would have spent years waiting for someone to finally choose me and my son consistently.

I’m trying to grieve my mother, raise my child, rebuild my finances and career, and create a stable home for us.

Meanwhile, I feel like he gets to walk away, reconnect with another woman, go out, drink, have fun, and potentially start a new relationship while I’m left carrying all of this pain.

For those of you who have experienced something similar:
How did you stop comparing yourself to the next person?
Did your avoidant ex treat the next partner better, or did the same patterns eventually return?
Did they ever process the breakup after the initial relief or distraction wore off?
And most importantly, how did you finally stop waiting for them to regret losing you and start accepting that the relationship may truly be over?

I know social media is feeding my anxiety. I know I need to stop looking.
But right now, I’m struggling with the fear that I was simply the woman he practiced on before becoming a better man for someone else.