I do not have a safeword, and if my partner just threw his hands up and said, "This is too much for me right now.." and left the room... I would curl up in a ball a cry..

This is yet another reason I emphasize submissives journaling.. ..and Dominants reading the aforementioned journals.. You can both have a better idea of where the limitations are if you are in sync with all the thoughts/feelings/desires that are difficult to discuss out loud..