Need some guidance....

[~¤DG¤~]

You should never, ever make someone a priority who only makes you an option.
Being devoted and wanting it to work is NOT telling OW that he loves her more than anything.

And no, you shouldn't have to abandon your wants/needs in order to save your M, nobody is worth sacrificing personal happiness. If you allow him to come home under these circumstances, your going to constantly worry if he's truly happy or thinking about OW.

I know we are here to try and save our M, but in your case I think you should worry about saving yourself and kick him to the curb.