You are dealing with so much. Did he know you were sick? And sometimes you have to take the griping with a grain of salt here, look at the type of relationships that we (or me) are addressing. When a young fluffy 20 something comes out with stars in her eyes and is in love and committed in 30 minutes, but oh my he's left me for four months, and he's treated me badly, most of us will not beat around the bush about telling that person to take a hike. And then there are those who have been living with bad behaviour, not just the crap that PTSD throws at them, but vile behaviour. Those ones are another target of the Get Out of Dodge lecture. The rest of us slog along like anyone in any relationship. We laugh, we cry, we have ups, we have downs, we support, a lot. But we do get something out of the relationship, and there is give and take. For my part, the Dude doesn't have a lot to give, there's more to his story such a crushing divorce that has left him with literally nothing. As he trusts me, he is able to give me those things you are talking about. I work so I can do mission work a few times a year. He says this is part of my job. My ex thought all I was doing was going out and having fun. Try having fun floating on the Amazon just after rainy season in July. When I questioned him (the Dude about why he thinks mission work is part of my job, he said it's what I do, makes me who I am, and is a part of me. That's just an example of ways he supports me. The kind of support I need.
I'm not sure if your cancer is considered cured, or in remission. What I want to do is tell you to throw caution to the wind and live and love. Life is too short. But I can understand your concerns. Take your time with him. Maybe it warrants just a coffee as friends. I don't know if you are setting yourself up for disappointment if you do venture out with him. Only you will know, I guess. And forget the what ifs. You can only deal in the present. the what ifs can drive you crazy. Good luck :)