In a fantasy world our loved one will discover our secret desires, embrace them, and make them come true. Oh, if only it was that easy.
Don't do something nice, then spring the fantasy on them. No one likes being set up. 'I've done something nice for you, so you can do what I want' is tacky and manipulative. Pick a nutral time, (e.g. a long weekend) which gives your partner time to think and digest. Be accepting, if the answer is 'no'.
But then there's always the fantasy...
1 day ago