For a long moment, Marcellus only continues staring down at Winter.
He decided to keep silent since he didn't want to say something he didn't mean. How she always pushes him to see other women is starting to get on his nerves. She did notice that he was no longer going on dates as much as he did before, but she ended up reacting the complete opposite of what he wanted -
He thought she would find it a good thing.
'Can't you see? You're the reason why I don't take women on dates anymore,' was what he wanted to say but could not find it in himself to do so.
Right then, Winter saw how desperate Marcellus was starting to look.
She wants to know what he's thinking. She knows that there's something he wants to say.