What is this "too much" sex you're talking about?About 8 fuckings in a 24 hour period. Each one lasting about an hour.
So since you see her 2-3 times a week, how are you managing this time wise while taking 18 units and maintaining your honors status? Also idk why men think longer time doing the deed = better... if you gotta go that long she probably has to fake it to get you to stop cause that would make her stretch out, dry out, and be sore not to mention smell bad given the amount of times you claim to do it in a 24 hour period, weekly. One thing you might consider too if this is legit, which i doubt, is that maybe she finds you so boring to talk to that she figures doing it is the easiest way to shut you up while fulfilling her girlfriend duties.