If you are having sex and just can't finish, do you fake it or are you just honest with your partner

Honesty is always the right answer and when those situations have occurred honesty is what I've always gone with. Because honesty opens the door for conversation which can bring about understanding (my head was off elsewhere, I'm more tired then I thought I was, etc) which then allows for finding a solution and/or compromising. Plus I feel it's a good rule of thumb in general to be honest about anything with the person you're physically intimate with, granted for me there's no chance of sexual interactions if I don't feel emotionally safe, so your vantage point may be, and probably is, different.