How to break up with GF without hurting her?

We've dated since November. Everything is perfect. She's the perfect GF, i have no complaints. However, i don't have the time of day to be there for her when she needs me, we don't see each other much. Only on Sundays and even then less than 3 hours. I also have to divide Sundays into relaxation for myself and seeing my family and gym. Right now i realize isn't the best time to have a GF, i can't make extra time for her. So how do i go about breaking up with her this Sunday without hurting her and making her think something is wrong on her end?