(NSFW) How to express needs to my wife?

I was hoping to get advice about how to express my physical needs to my wife. Long story short she has been very sick over the past 6 months. This has consisted of 3 months in the hospital. She is currently going through chemo and we have a lot ahead of us. We’ve been home for the past 2½ months and we have had sex quite a bit since we’ve been back. But over the past few weeks it has dwindled.

But when it comes to our physical relationship, I can feel guilty expressing need. I obviously want to be sensitive and have compassion, while being able to communicate my needs . Help?