ever thought of it from their perspective?
Their girlfriend seems reclusive, and in a sense has more of a prioroty for work than them. Have you ever wondered why they are asking you to do stuff with them, as apposed to work. To them you probably (At that time) mean a lot to them, they want to spend more time with you and develop the relationship. The guys aren't doing anything wrong, and neither are you really if your prioroties are towards work.
2 of them were actually class A grade students who prioritised studies even more than me!!!!
that comment intruiges me, it suggests that you find those who priorotise work over you as a poor choice for a bf. Cant you see where the guys are coming from now?
I mean you dont have to spend days on end with your partners, but nice guys would love a day a week and maybe a few nights with their girlfriend - they are going out with you because they like you!