Yes he is hoping you'll be his Plan B. They're not thinking logically but emotionally. All he knows is he's in pain and trying to run from it. He doesn't realize that wherever he goes, there he is.
You don't need to make any decisions right now. Do see an attorney to learn how best to protect yourself financially while in limbo. Then get out and live a life so fun and exciting he'll want to join you.
You need to minimize stress and maximize joy as a cancer survivor.
I repeat my suggestion that you arrange a fun vacation or weekend getaway with a friend or your sister-or on your own! Let him wonder if you're going to meet someone while you're gone. Do something out of the box.
Also, consider changing your hairstyle or color, buying new clothes, leaving that Victoria's Secret bag out where he sees it. The goal is not to start dating but to give him the opportunity to feel some of the loss he would feel if you HAD moved on, to give him a chance to snap out of it before you've actually moved on.
And regardless it's a good idea to work on strengthening your circle of friends. The truth is as women we are more likely to outlive our partners and friends and family are key to living rich lives. I saw a single, childless new patient in her late 80's and she told me how she had a circle of friends who have agreed to care for each other as the need arises.
