It is the logical thing to do, and yet, it hurts so much, because feelings are such intangible and ephemeral things. I hate to consciously make decisions based on feelings, because I find them unreliable, as I, being an INFP, can over-analyze everything I feel or think until it becomes a nonobjective piece of mush that is useless to me. They, again, are also so ephemeral and evanescent that it's really hard to catch and cage that essence and feel it consistently for a long time. When you make the final decision on whether to break up with that person or not, it may not be the right decision to make, because there are so many different shades of feeling, and feelings change over time.
The feeling of love to me is like water: you can't hold it in your hands, and the harder you try to keep that feeling, the faster it will silently slip through your fingers until you can't feel it anymore,
Sorry for that rant. Guilt is pretty normal to feel, too. I particularly felt nothing but guilt at my inability to return affection so easily and plentifully given to me, and infinite depression and sadness at how everything, even the purest of things, can come to an end and leave two people, once so happy, so incredibly bitter.