In a hotel, 'I have a room upstairs, if you're interested...'
This refers to the potential of having sexual intercourse + / - other things with a person who is largely a stranger. If this hint is proposed to you, would you say:
"O ! Yeah!"
"I'm sorry, I am married."
"I'm sorry, I am seeing someone (but damn, you're yummy!)."
Shouldn't one rather say,
"I'm sorry, I'm in love with someone, and would much rather sleep with him/ her."