70-yr-old husband

My husband is 70 years old, and we've recently been having some problems with ED. So far we haven't used any drugs, even though I have a sample bottle the doctor gave me. We have resigned ourselves to the fact that having sex is something we have to work up to over time instead of just something that happens spontaneously. I play with him a lot, and we do a lot of cuddling and smooching. I tell him that I need to rev him up for several days in advance to get things working. Sometimes it gets hard and then collapses without anything happening. Other times he can't get to a climax. However, every so often everything goes off like clockwork. It all just takes some effort.