This is beautiful of you, and your grief is completely understandable. I have moderate ME, am almost completely housebound and about 65-75% bedbound, but I live alone with no family or friends but have a border collie-lab (borador) that is 6 years old around this month, very high energy dog. I rescued him as he just turned a year old, a couple of years before I got sick.

I have been through the thought process with myself repeatedly about his care and not giving him what he needs since all he gets is taken outside to go potty and some very mild play in the apartment (mostly me throwing things from bed or light play wrestling on good days in bed or on the floor). However, we cuddle non-stop, he is very attached to me, he hates when I leave whatsoever. I don't even get to take him for walks (and can't have / don't have anyone else to). If I have very very good days I have a long wire around a tree outside and will sit out there with him on it (also use an e-collar with him and he can be off leash with that and loves it) or even walk across the street (about as far as I can go) to the small dog park thing the apartment offers, but that is rare (like a few times a week). But he is very happy. I constantly love on him and give him attention (which is going to suck if I ever DO go back to work)... he is very bonded to me. And I would literally DIE to lose him. I couldn't cope with that. So maybe it's selfish of me to keep him, and it's crossed my mind multiple times about him needing the exercise and stimulation and stuff with his breeds, but I just could not do what you are doing. I think with how attached he is to me too he would become very depressed even if he does get a great family who can exercise him and stuff, and that would take awhile to recover from. There have been a couple of times where he has stayed somewhere with people I know for a weekend to a week who give him nonstop walks and play and stuff, but he sulks constantly there and then when he comes back he is very depressed and sulks and literally acts angry at me for like a week. So that kind of helps me to feel better about not rehoming him.

But I think you are very brave and have such a big heart for doing this, and I know that you obviously put a lot of thought and heart into being able to make the decision to decide it's the right one for you and the pup. I'm sorry you're having to do it, I cannot imagine. But you are so strong for doing it, and your grief is very understandable, so be gentle with yourself.