Faithfulness in Christian marriage entails that: great mortification. For a Christian man there is no escape. Marriage may help to sanctify and direct to its proper object his sexual desires; its grace may help him in the struggle; but the struggle remains. It will not satisfy him–as hunger may be kept off by regular meals. It will offer as many difficulties to the purity proper to that state, as it provides easements. No man, however truly he loved his betrothed and bride as a young man, has lived faithful to her as a wife in mind and body without deliberate conscious exercise of the will, without self-denial.

J.R.R. Tolkien