How ever can I cope with myself to get through this time of insecurity? I'm afraid of losing him - silly really, because there is no reason I should.
It's not stupid... .I find myself thinking the same things, especially when I didn't understand what was going on when he went on a rage and said such hurtful things. There are times where my dBPDh shuts down and doesn't talk much. Same as you... .head nods... .one word answers. Then, other times, he talks for hours on end, sometimes repeating the same train of thought over and over again.
With him, I realized it was going to be feast or famine. One the days where it's feast, most often he is on the verge if a dysregulation, so I smile, hold eye contact, etc and let him get it out. During famine times, I have my own hobbies and my children I entertain myself with.
I guess you have to get to the point where you understand it's not you. Your fear is only because part of you still questions yourself, did you do something wrong? etc etc when you haven't.
Do you have other ways of satisfying those needs on Sundays?