You said that your oldest son always pays on a date with a woman whom he asked out, because he is a man. So, according what you exposed, his gender is essential for that action.
However, as the date is involving another person, that decision may not up only to him sometimes. For example, and if the girl refuses, wanting to pay? And if she persists?
Case he is invited to a date and accepts it, also would he pay all its bill? It is possible things get out of control. And if the girl brings him to a very expensive place, where he does not have enough recourse for the date there at the moment?