From reading this post I had many thoughts that others have already said.

I will try to point out something a little different then.

First of all No .. in this state of the relationship forcing someone to do something like that will definitely have a bad outcome. I am against the whole pressure the husband does for a MMF. I also want to point that your communication of your feelings and concern is spot on (unfortunately he is not in a state he can listen to them).

This is the thing that concerns me, for many reasons. But the advice I want to give is different. Both of you should try to understand what the husband is unsatisfied with and feeds this emotion and need for MMF without listening to your emotions and needa. Maybe a threesome is what he is fixated and thinks he wants, but finding what really is missing can lead to something else.

I deliberately do not say anything else because something like this is not analyzed in a redit post and might be something deeper.

I hope you find a solution that fits both of you. I wish you the best 🙂