My wife has a chronic illness that means that she's often not feeling up to sex. She feels bad about it, so when I initiate things and she has to say no, not only do I feel rejection (despite her no not being related to lack of interest), and she feels bad which can perpetuate the not feeling up to it part.

She knows that I'm down for anything at any time, so what's worked for us is I give her a back and leg rub most evenings, and if she wants to go further she spreads her legs a bit to give me permission to start foreplay.

I guess that technically means I initiate it, but only after getting permission to do so.