It is very pleasant to scratch an itching ring-worm, but the sensation one gets afterwards is very painful and intolerable. In the same way the pleasures of this world are very attractive in the beginning, but their consequences are terrible to contemplate and hard to endure.
You must be aware that most men (and also not only a few women) are by nature not monogamous. This nature makes itself even more forceful when tradition and circumstance stand in an individual's way.