Cringe 'R US
I'm not cringing over your question, I'm cringing over your crass choice of words to describe your situation. I gave up being a psychic a few years ago, therefore I don't know ahead of time what I'll be getting into once I start reading a post. lol
Now, as for your poorly worded but perfectly valid question:
It is a possibility that the reason the penis is unable to remain inserted in your vagina may have a lot to do with your partner losing his erection. Whenever a man can't maintain an erection during intercourse, this is usually what happens, much to the dismay of the female partner who inevitably begins to feel like it is her fault. It's not. Nor is it his, "fault" that is. There are many reasons for failing to have a lasting erection, few of them which have anything to do with the woman nor how he feels about her.
Meanwhile, you did mention on an earlier post that you yourself were suffering from vaginitis, the causes of which are some sort of infection, ie., yeast, bacterial,...etc.
So perhaps there are a lot of physical issues here, not to mention some complex emotional dynamics, which could be affecting your intimate encounters.