When we think of human relationships, the relationships between people, whether friendships or romances, we often come to a point where there is a parting of ways - a place where friendships stop being rewarding, when a love relationship ceases to be a love relationship and just devolves into something less. Just like a marriage where the love has exited stage left, all things end - and attempting to keep them alive artificially serves no purpose other than to drag things out to the very bitter, painful end.
Guilt shouldn't bind you to a person or trap you in a failed relationship. If it isn't love that keeps you there, but guilt - then you're both better off with someone else - or alone, because otherwise you will be doing yourself (and each other) more harm than good.
In many ways, the same thing can be said about religion.