This is such a beautiful song. I think there's 2 scenarios. 1.) He had an affair or a dalliance ('i just came across a manger out among the danger, somewhere in a stranger'a eyes) and the whole song is him saying to his long term love or partner that he accepts whatever she decides whether with him or without as he just loves her, no one else and he realizes what she means to him now and he doesn't want to change her. He just gave in to temptation. At the end 'i just came across a stranger, where this is no danger where love is blind it needs no eyes. So it's proper love with his love. 2.) It's about someone he is in love with. Maybe unrequited but he will take whatever he can from her. He doesn't mind as he just wants her to be her and not sacrifice herself. Again the manger line, she was safety and appealing.