So many other things to think about during the most difficult transition of your life. First, you're just trying to make it through this, you just want to survive. Many relationships suffer due to the uncertainty of the outcome of this period. Mood swings, depression, the daily regimen, etc., may even cause a couple to breakup.
However, perhaps after completing the treatments, the thought of resuming things you enjoyed before the diagnosis comes to your mind. Depending on the kind of cancer, you may have lost your hair, breast/s, etc., and furthermore, you're not fully adjusted to the new changes. This is the time to go at your own pace. You may even need to go for counseling or attend a support group.
One things for sure, you are not alone - listen to their journeys:
A Fun Couple - The Alterowitz's
Medical Expert - Dr. Jacques Moritz