I have heard from some people that they enjoy watching porn with their partner during sex. I have also heard from many people that fantasies involving celebrities are a normal and harmless thing (for the relationship). Many people (even on this forum) seem to share these views, and my question to those people is how do you know it is harmless? How do you know that it isn't a sign that things aren't going well for you (that one of you is unhappy with the relationship)?
The celebrity fantasy example seems to be the more problematic one to me. Just imagine what it would be like if your partner had fantasies like that about someone you knew, maybe a friend. How would that make you feel? Now, is it fundamentally different to have fantasies about celebrities as opposed to people you know personally? I would argue that it isn't. It surely is more unlikely that your partner will dump you for a celebrity given the unlikelihood of meeting him\her, but the underlying problem is still there, regardless of the object of your partner's fantasies. He\she probably feels more attracted physically to that celebrity and would probably dump you for a similar looking person. Wouldn't you agree?
I think that this is either a problem with monogamy, which is to say that it doesn't work well at all, or you can simply avoid these types of situations. I think that such situations are avoidable to some degree. Just because you spot someone attractive (perhaps even more attractive than you partner) on the street it doesn't mean you have no control in choosing to think about them or not. You can simply choose to think about something else or even stop thinking entirely (the latter being much harder to do). I would argue that the same is true for celebrities. I have been attracted to quite a few female actors in the past, but I don't recall ever thinking about them for long periods of time. I just thought they were beautiful and I pretty much moved on (but then again, I don't really get the fascination with celebrities).
So I would argue that this is a matter of concentrating your attention on things that actually matter, and that you can avoid thinking about these things and eliminate the problem pretty much altogether.
What do you think? Are fantasies about other people unavoidable and harmless in a relationship? How can you justify a behavior like that?