To the people on here saying it's not at all weird to have an imaginary conversation with somebody famous, (and pretend you're having an affair,) or to pretend you are a famous rock star, or you have a secret second life in your head; I will ask this......
If it is perfectly 'normal' behaviour, then why not tell everyone you know - neighbours, family, colleagues, and friends, what you do??? Why not tell them all about your 'weird little world in your head.'
I am not saying it means someone has a mental health disorder, but no way is it normal behaviour. The fact that the OP is mortified that her DH heard her, and a number of other posters said they would be mortified too, shows it CAN'T be normal behaviour. Otherwise, why not tell everyone you know about your 'weird other world.'
If someone is living out another life in their head, and imagining scenarios far removed from their real life, that is definitely a sign that something is missing from their life, and there is definitely something missing from their relationship, because this is just very weird behaviour....
And the 'hey I'm well quirky and a bit mad LOL!' line that some come out with is tedious and tired.
This thread is, (IMO,) a lame attempt at trying to get into 'classics.' yawn........