It sounds like the misrepresentation you are talking about is serious and troubling to you, otherwise you would not be posting about it. I understand your need to keep things general.
The problem with these pretensions is that with time they get worse, not better, and those who go along with them tend to get sucked in deeper and deeper. This can lead to many innocent people getting hurt because eventually, when the cheat is detected - and it usually is - it will look like they were "in on it".
As Howard suggests, I would steer clear of this guy. You can say you bear him no ill will and you understand he has needs too, but you can also say that where your recovery is concerned you can't put his needs above your own. This isn't a selfish thing to say; it's a practical consideration. Hanging on will just drain away your resources and distract you, and you should also ask yourself this: "How can I be strong for anyone else when my ability to be strong for myself is being undermined?"
The plain fact is that it was wrong of this guy to put you in this spot in the first place, and it's even more wrong for him to expect you to remain there now that you know.
If you wish, Mike, PM me or another moderator and we can discuss this by PMs or in chat. You can rely on our discretion and perhaps that would enable you to speak in somewhere more specific detail.
Nobody living can ever stop me
As I go walking my freedom highway.
Nobody living can make me turn back:
This land was made for you and me. (Woody Guthrie)