When is it time to let go?

At what point do you just give up and walk away? I love my husband dearly but I don't know that I will ever be able to help him. I try and try and just dont know how to keep going. I've always supported him. I don't want to imagine life without him and I don't want to break my son's heart. We are all my husband has. I fear for what could happen if he lost us. Dear Lord, please give me the strength to carry on and guide us in the right direction. 💔😢