Deedee is the only mystery to me. She has a decent job and stable finances, as evidenced by her not-cheap condo. Why does she put up with Nader? She's not such a drunk that she can't hold down a job, etc.
I'm sure she's just lonely. She's not desperate for a True Love like Chantal is, but she's desperate for anything fucking interesting to happen in her life.
What does she really have? A dead-end job checking boxes at an import company (as per the person who claimed to work with her). A 600 square foot condo in a nowhere suburb of Montreal, which Nader has hinted she inherited from her mother once the old woman was in a home. She has a singular friend we never hear anything about and who, if she existed and was as close to DD as it sounds, would surely intervene in the whole Nader situation. She's financially stable and overall a step up from Chinny's chaotic never never land of filth and Peetz, but realistically, she doesn't have a lot going on. She's a catlady without cats.
Once her husband (or whatever) died, her entire life stopped. I'm sure he was just as domineering, narcissistic, and borderline abusive as Nads by the look of the state of her life now that he's gone. I mean, assuming he existed and DD hasn't been this marginal, overweight office lady since she left high school.
She obviously doesn't care about infidelity or being "claimed". She just wants someone around to "cook" for her, smoke with her, and party with her on the weekends. I don't think she even really wants him in her condo at this point.
What's astonishing to me is how Nader has played both these women into hating each other, to the point DD is threatening to sue Chantal. (Either that, or he's convinced her to get in on the grift, but I think there's actual dislike on DD's part at this point.) Nader seems to be trying to insist the conflict/drama is between the two of them, and he's fine living with DD and fucking Chantal. Of course he is. If DD sues Chantal and wins, you can bet he'll be spending that settlement on more tracksuits and meth, then once Chantal's calmed down, going over to her place for more of the same.
He's unbelievably pathetic.