I'm feeling like I need him again- how do I get through this?

Narc D&D me for the 5th time recently on Friday night, going back to OW. At this point I was totally ready to break away and go NC. I was fuming at the cheek of what he had said to me and how he had done this AGAIN, and angry with myself for allowing it to happen again. I had gone all weekend feeling very strong and calm but today I feel like crap. I've not heard a thing from him since he left me again, and I'm ashamed to say that I'm missing him.
I can't understand how he does this to me. I have no respect for this man- he has lied, cheated and stolen from both me and OW. One minute he's madly in love with her, then me, which is laughable. He is possessive and controlling. He has severe mental health issues aside from NPD, he doesn't work, he sponges money, we can't even have proper sex most of the time as he has impotence issues (caused psychologically) and has been prescribed Viagra but is too scared to take them as he is a hypochondriac and is worried they will give him a heart attack, so no chance of it improving either. I'm fully aware that he doesn't love me, probably doesn't even like me, and has used me for nothing but supply. And yet he still leaves me feeling like I need him, like something is missing without him. And I can't understand why as I totally understand what is wrong with him now and that he can never make me happy and I don't want this anymore, I swear to god I don't.
How do I get past these pathetic feelings and stay strong? I have to stay NC I cannot let him do this to me again and win