You say he wants to remarry............how do you feel? You know what he has done, and how he did this to you when you needed him most. Are you prepared to forgive him for this and let it go? The reason I ask is because in the end it really does not matter how much you love him or how lonely you feel...........if you can not forgive him for what he did to you then you will always hold that in your heart and eventually you will come to resent him.
I can not tell you what to do, only you know what you really want and what you really need. I can tell you that what he did was not only incredibly selfish but was deep down wrong. Regardless of how he felt he made a vow and he broke it over his own insecurities about your illness. He had it good.....yet was to shallow to see beyond his own desires. Is that what you really want in a partner.
Life is short as you have already learned.........you have looked death in the eye and come back fighting! To waste that on a man who has no more spirit then he has seems a travesty to say the least. Though in the end what you want and need is far more important then what I or anyone else thinks about him.
What I would suggest is sitting down and making a list of the things you want and need out of a partner and then consider how your ex stacks up against what you need. If there is enough reason to give him a second chance then do so......but do so with eyes wide open. Do not jump blindly into this relationship. Insist on marriage counseling and set down some ground rules. I would suggest taking this on a trial run before remarriage that way if you simply can not give it a go, you have a easier way out then divorce.
If after weighing your needs against who he is you decide he is simply never going to be what you need I would suggest opening up to find what you do need. Just because you can not get out does not mean you have to stay single. Consider online dating sites, I know it seems odd or even frightening but the reality is online dating sites cut out all the middle boring dates and give you a chance to get to know someone before investing to much time in dating.
In the end you have done a amazing thing........finding love and happiness is nothing compared to what you have already done.