She collapsed on the floor because she wasn't feeling well and he just stood over her, told her to stop acting and left her there. Didn't even try to see if she was okay. I was so disappointed and that ending was really stupid. He didn't even apologize for abandoning her in her time of need.
I've never been so disappointed in a book before. This had so much promise and started so well, Darcy was cool, unemotional and had the sense to realise Renzo couldn't give her what she needed and the self-respect to leave him before he inevitably hurt her. But after the holiday in Italy everything goes downhill. Darcy gives into Renzo and becomes his kept woman, he gives her a diamond necklace which her friend steals, he accuses her of having seduced him in order to steal his fortune (despite her being a virgin when they met, despite her emotional distance during their relationship, despite her repeatedly trying to break up with him long before the theft, despite all evidence to the contrary!) and dumps her. The last straw is after she finds out she's pregnant she gives in to Renzo's horrible blackmailing and marries him to "protect the baby". At this point she abandons all dignity and self-respect she had, to fall into all the worst Hq tropes. Plus the translation's just terrible.