No, it is NOT okay for a man to have sex with a man after she says no. No, a woman does NOT owe a man sex just because he buys her dinner or treats her nicely. Sex ALWAYS has to be consensual. A man should NEVER pressure a woman into sex, and a woman should know that she is NEVER obligated to have sex unless she wants to. This holds true for same-sex couples as well. No one ever has the right to demand sex, and no one ever "owes" sex to anyone else.