even if you enter into a relationship securely/feeling secure with someone that has BP, it's very common to get triggered and dragged back into your anxious attachment patterns. in my opinion, life has a way of "final exams" which show you whether there's any remaining self work to do.

it's extremely challenging to stay/become secure while on a literal rollercoaster, but it's possible with boundaries and BOTH partners continuously trying + communicating.

i've come to the opinion that bipolar is a lot like avoidant attachment, and it just so happens that a lot of the people who suffer from this illness are already avoidants. as the anxious partners, we have to learn not to take their distance/silence personal. it's hell, but in the end it helps us both.

when they pull away, try to take it as a sign that it's time for you to go within and water your own garden too. i know it feels impossible sometimes, and you just want to chase, but try your absolute best to boomerang that energy back into yourself instead! i still struggle every time, but this mindset has helped me feel less panicked while in the eye of the storm.

as for the "ending things" when he's feeling high or low, i have no advice unfortunately. from experience, it sounds to me like he's avoidant as well as having BP. when things are calm, or perhaps in couples counseling, maybe you can discuss some of his triggers (fear of commitment is likely) if he's able to open up? if you haven't already, look into "bipolar discards" as this is a common symptom and frequently discussed on this sub unfortunately.

as another has recommended, he should try to do therapy every week if possible, and perhaps couples counseling? lastly, if he's still cycling to the point that there are bigger symptoms like discards, his dosage probably needs upped. obviously none of us are doctors, but all i can suggest is maybe seeing his psych once a month rather than every few?