It seems that your husband is sleeping with you because he’s scared of the shame if and when your adult children find out that he has cheated. He would do anything to avoid that. You already know this but you are able to ignore it for now.
In the meantime, you are also scared, -scared to face a lonely retirement without him by your side, providing support for you as he always has by going along with your arrangements for your lovely life.
You readily admit you are controlling (you have put paid to his affair) and that you have twice threatened suicide which as others have pointed out, is emotional blackmail from which no good can ever come. It’s on you to be accountable and take responsibility for that. You say you are doing that already so that’s a good start.
Is he pretending to be in love with you OP because he’s scared of the consequences if he doesn’t ? Letting him continue to pretend can’t be very dignified for either of you, surely.
It will take time as well as courage for you both to face up to the fact that your marriage has changed irrevocably. How you make the practical day to day chnages to reflect the change in your marriage is up to you as long as both of you are willing and happy with the changes and as long as neither of you is coerced or controlled or threatened.
If you love your ‘sweet’ husband, you will think in terms of his happiness as well as your own. (not just in terms of him providing support and company for you)
You can’t turn the clock back to the old days before his affair OP. They weren’t good old days for him it seems. If he was as happy as you, why did this good man turn to a quiet woman for company? Why did he jeopardise the easy-ride retirement you were expecting?
Be prepared to communicate with complete honesty and to make a lot of compromises and never to take him for granted again. Be sure to make sure that any changes, are really what he wants. Ask him what he really wants. Encourage him to be openly honest. No more pretending just because it suits your cherished idea of retirement.
Maybe it won’t mean divorce as long as you are prepared to respect his truth as well as your own. You may still be able to remain together and enjoy your retirement -or parts of it, together.
Wishing you both well with the counselling to properly fix this.