Have you asked them if they would want that? Serious question.
Edit: sometimes I think we are too shy when it comes to telling our friends about our feelings and wishes and too judgemental when they tell us theirs. Why does knowing something intimate about each other have to be awkward? I'd rather have them tell me something I don't want to fulfill than find out after 20 years that there's something we both wanted and never talked about.
No, please do screenshot it and draw in red arrows because even on the fifth read I'm not sure if the two of us have read the same post. I can't find the passage you mention nor anything that hints at OP being female.
Edit: now that I've read it a sixth time... do you really mean the "I can’t face the reality that they might leave rather than watch me do my own thing." sentence? If so, you seriously need to get your mind out of the gutter and check if you are the person who should check their reading comprehension skills. That sentence has nothing to do with cuckolding or voyeurism.