Is it always worse to be unfaithful by action (having an affair) or by thought (fantasising about a person)? An affair can last for a while without the adulterer's partner ever even knowing about it and when it's over the adulterer may, in some cases, have a more favourable regard for his/her spouse. However fantasising about a person can go on indefinitely and the spouse is then always compared unfavourably with the love object - and the person fantasising is perpetuating an "in love" state which will keep him/her somewhat detached from reality. What are your views?

Following up on what Prof. Solomon says, you might want some way to assess each case on its merits. So you might think about what makes an affair wrong. Is it the betrayal of the spouse, or the effects that the affair has on the spouse? Some people might think: if my spouse had an affair, then even if I didn't know about it, and even if it made him behave nicer to me in the long run (perhaps because he came to appreciate me more), it would still be wrong because he would have betrayed me. On this view, the betrayal is bad independent of any effects it has. But some people locate the very badness of the betrayal in its effects: my spouse treats me poorly, spends our money indiscriminately, etc.; maybe other people, treat me differently as a result of the affair (they might look down on me and think I'm a fool, etc. etc.) And of course, maybe the affair leads to a breakdown of the marriage, which has all sorts of devastating consequences... Now, regardless of whether you think that the affair...