I get what you mean and agree it's one possibility; however, don't we all have an "innermost being" that is different than who we really ultimately want to be? A person can have many sexual or aggressive impulses (and curiosities about experiences), but there's a lot more to life than satisfying momentary impulses, such as love and parenting. And no one person can be absolutely everything another individual may desire over time.
Case in point: A relationship can only be new once. Thus, Hutch cannot give Vivian sexual novelty, at least not in terms of the sexual excitement one experiences when having sex with a new person. Vivian made the comment at one point about how long it had been since she had worn a certain nightgown for Hutch, and that the last time she did he was "a real animal that night." Sure, this might have been her embellishing to try to cheer him up, but I think she was referring to what really happened; otherwise, why fish the nightgown out to try to make love to her husband? Plus, Hutch was a younger man once (with greater sexual prowess than currently), and sex with his wife also would not be as new or exciting for him as it once was, even if he truly loves her.
I think there's no denying that the boss is blackmailing her to some extent, regardless if he says it's all in her head. When she visits him the first time, he implies that he is going to fire her husband unless she attends dinner at his home. Then in the restroom (in order to coerce her into having sex), the boss mentions possibly having to lay off many people due to numbers being down at work, thereby trying to make her feel responsible not only for preserving her husband's job but also the jobs of others. The boss is a slimy sociopath who has manipulated a series of women into having sex with him, and he undoubtedly has moved on to the next after getting enough of what he wants, just one "conquest" after another.