How do you deal with the push away phase?

If you're secure, you won't take it personally and you'll know that if you take the space being offered, it will flip back again at some point.

But is that how you want your relationship to be? Does it meet your needs enough that you're able to accept that behavior and not try to change the partner or dynamic (once you've directly communicated about it, shared what your own needs are, and had a dialog about it, of course).

Not sure how this might play a role here, but my fear is really that he is capable of hurting me at my most vulnerable without that emotional connection. He might not leave me physically, but if he stays in a relationship with me whilst pretending that he's emotionally invested, it opens up so many ways he can hurt me with no remorse (and I wouldn't be watching for these signs because I trusted him to care about my emotional well-being), that's a scarier thought than being left alone. that is why that emotional connection is so important, because for me, it represents safety in vulnerability, for both of us. the trust erodes when you're never sure if you can be safe in your vulnerability because you expose yourself to risks that are unstable and uncertain. There's a difference in normal ebb and flow versus strong emotional withdrawal - i think it's the extent of withdrawal and how one comes back to the relationship that matter before this erosion of trust starts. 

My DA started his first push phase and I had to pursue him, and it suddenly and violently ended when I visited him on a business trip. Meaning, he was suddenly all over me and simply pretended that nothing happened. for me, that was extremely traumatizing and i never really recovered from that, because how can i trust that the good times are actually real. It happens only when he feels like he wants or needs it, and it makes me feel like i'm his supply. there was also never really any sense making around it, and all he said was that he doesn't remember what happened and that he simply thought nothing was wrong. to him, that might be very true, but to me, he's gaslighting and manipulative, and I never trusted him again. I was emotionally reacting because that was how i connected with him - emotionally, but it is now clear to me that i cannot be 100% emotionally resonating with him, because any movement he makes creates a big reaction in me.

This is one thing you must keep in mind - your emotional connection with him cannot be the only way you're connecting with him/her. If that is the way you're connecting, you are 100% linked to their emotional movements and everytime she/he does something, the reaction you'll have is 100%. you need to treat him as an independent unit that is slightly overlapping with you, but the majority of you is separated from him.  

i would say that you need to just be mindful of what happens during the push phase and take notes. No emotional reactions or investment, just see what this person is like in his/her push-pull phases, and see if that's something you want to deal with and how you can deal with. So things to note: behaviors during the push phase, behaviors when returning from the push, and behaviors during the pull phase, and how different and unstable those are. if they're just slightly different in intensity, i think it's alot easier to manage. but if those are intense difference, you need to make a good judgement of what you need in order to protect yourself and eventually, if it comes to it, how to communicate that with him/her. 

I accept that I have no control over it, and that it's not my fault, nor his.
When they're distancing, you're not missing out anything. They'll be back and it feel great again so as long as they don't do anything that I'd consider a betrayal, I'm ok with it. I asses where we stand, how good or bad it is between us when both of us are in the right state of mind.

When they need their space or they are actively pushing me away I stop engaging and use that time to focus on myself. I became happier and more secure thanks to it.

But that's up to you to asses if this kind of dynamic is ok with you, where do you want this relationship to go and what kind of person they are.

I, on the other hand, would advise not to listen to your gut. At least to me- gut feeling= activated attachment wound and unconscious fears.
What else an anxiously preoccupied person can feel when someone disappears or pulling away? Is their narrative always right? Should they act on it right there?

If you act on your gut feeling is because "perhaps" he is not right for you and "perhaps" it will be better that way, if you become act secure and mindful there will be no "perhaps" and doubts. 

But there is the opposite argument of staying in the relationship for fear that you will miss out or perhaps it is your issue when maybe it truly is a case where that person isn't a good fit.  In general, I have stayed in unhealthy relationships for far too long assuming that it was only "my issue" and that if I could somehow make a square peg fit into a round hole the relationship would end up "ok". Sometimes to get to a state of secure, a person has to be willing to let go of a relationship that isn't working.

this.
i agree with all from you in this thread and ultimately support " keep growing and you'll know when and if to let go"

ultimately, the push phase is destructive to a relationship.
over time there needs to be growth out of it.
i have worked very hard to remain consistent during deactivation and require consistency from a partner.
i'd rather be single than repeatedly shut out- that dynamic doesn't meet my need for stability and drama reduction.
life is too hard to have to strap in for a roller coaster relationship.
it's very hard work to overcome these patterns but ultimately if you work at it you tend to outgrow the dynamic, not get better at surviving it.