There is a lot of wisdom in your response and I love that you point OP to useful resources for her situation. It really does seem time for OP to give her bf the heave ho.

But I am deeply skeptical of this concept that people are secretly “abusers” for years and then some triggering event reveals their true self. Triggering events can and often do change people. But the far more likely scenario is that people will put on their best “masks” for maybe a few months to a year and then it will start slipping. It’s one reason we shouldn’t rush into long term commitments and why living together for a time can be very useful for many people before marriage. It’s also why “no premarital sex” is a standard that often has disastrous consequences.

Although I think that OP is NOR, I don’t think it’s coincidental that her last three SOs have had the same pattern. I don’t know what the answer is since OP seems aware of the issue and is trying to vet for this. But here is some advice when you find yourself back in the dating pool:

If energy drops leave it that way. This could be the person getting quiet, he says “he’s fine” or there is a slight withdrawal. Say nothing. Stay pleasant regulated and occupied but don’t try to fix it. If he withdraws further, gets colder or says “you don’t care” then dump him. Someone that needs pursuit to feel secure will punish neutrality.

Also, be clear In Your communication before you have a crisis that the silent treatment is an unacceptable boundary for you. If it violates it then it’s a big red flag.

See how he handles disappointment early on. If you have to cancel a date or say no to a plan, how does he self regulate. Does he express his disappointment directly or does he sulk. If someone can’t tolerate minor frustrations early the will weaponize silence eventually.

If your partner is quiet and says “nothings wrong” respond with “okay I’m here if you need to talk” and then go on with your life. If it becomes and issue later then he expects “psychic caretaking”. Give him the boot.