Has anyone had a random sim student go against their sexual orientation?

No, that's the opposite. A male sim who is interested in women is basically a straight man. Two who are the same are both straight men. Why would they want to hook up? (One guy says to the other "Hi, I see you like women too, so let's date"?).

Anything else and I can see why you might think that. They both like ice cream, reason maybe to date. But if two men both like women, they don't want each other.