Why? so u can be lazy and not pay your share? Not all old men will pay for u forever, maybe for a little while, nobody gets a free ride sister also:
Old man can't keep dick up for sex, and u end up bored and cheat on him with younger man anyway. Also if old man has money he has money to spend on a couple girlfriends too:) y wouldn't he? He is old and about to die anyway so he live it up on your time.