I’m about to take my husband into assisted living in a few days. What do I tell him?

You are correct.
At 65 you are YOUNG and you have at least two active decades ahead of you; you need to stay healthy and very active.
What you tell hubby depends entirely upon his ability to understand.
It doesn't work to sit and patiently say "Honey, you know how much I love you, but your care is more than I can do now. You need me with you 24/7 and I can't do that. I need to know you are safe and cared for and I will visit you all the time. I know I found the right place and you will makes friends and be active here in a way I can't provide for you. I am so sorry, but this is the way it has to be for us now; I know it is tough for us both, but we have to do the best we can". It doesn't work if they aren't mentally there enough to hear and compute it.

If hubby is now very confused due to dementia you do the whole thing with respite, and then slowly it becomes "You doctor says that you will have to remain because aren't well enough to be in my care" and etc.

You do the best you can. And that's about it. Not everything can be made all peachy keen and that's been the way of it THROUGHOUT life. It isn't new that life isn't "happy all the time". If you have been together any amount of time then there have always been struggles. You didn't create this and you can't fix it and you are doing all you can to remain faithful to what is left in the relationship the two of you have had.

I am so sorry for the struggle.

Any "therapeutic fib" you tell him that you think he will accept is perfectly moral and ethical. I would make sure the staff knows, too -- they've seen it all and probably have gone along with other peoples' fibs.

I would be sure to talk to the admins and staff so they know you'd like them to encourage him to join in on activities and events. They can't force him, and at first as he adjusts he may not want to. It took my MIL several years and a really good staff to eventually get her to join in (and some of it was just dementia changing her personality).

I wish you all the best in this transition. You should not feel guilty -- it sounds like you tried other options. What you feel is grief, and that's ok and normal. May you receive peace in your heart!

I’d tell him that it’s respite for you for a month, doctor’s orders because you are ill?? Follow the AL instructions about not visiting for a couple of weeks so that he settles down. See how you go. If you bring him home for a week at the end of the month, provide as little as possible in the way of support, so that the AL seems like it wasn’t so bad.

Please don’t feel guilty for placing your husband. I am sorry that home health didn’t work out for him. Take comfort knowing that he will be cared for in his facility.

You can return to being his wife and advocate for him.

We have posters who have placed husbands in a facility. I hope they will answer your questions and address your concerns.

Wishing you peace as you move through this difficult process.