I empathize with you greatly and wish you to be well.

Your questions are not simple, nor are the attempts to reply to them easy, objectively true and more.

There are multiple possible explanations as to why you "'end up' in back to back relationships" of similar circumstances, behavior and more. Some examples are how you are (and are not) conditioned, your familiarity to such dynamics in relationships and people, you lack the necessary knowledge to identify warning signs before and/or during your history with the person in familiarizing yourselves with each other, you lack the necessary knowledge to heal from past incidents, whether it is trauma, hurt, heartbreak and others, you might just simply be attracted to people, who happen to be of similar behaviors as one another, and any combination of the aforesaid factors. There are more possible causes.

Also, just a quick note, upon research in such topics, there is no "type" of person. Labels of people are mere attempts to define people in order to speak about subjective aspects, but those labels inaccurately attempt to objectify a person when that cannot be ontologically done.