I am on 500 deadlines and everyone in my household is or recently was sick and I have no time but I cannot help myself.
It has long been my sense that sexual adventurousness as a category is something only used in reference to women. That there is no such thing as a sexually adventurous man, because this is what is referred to as a man. Not that all men are sexually adventurous, even in their own minds, but it is the assumed default state for men. It is women who are assumed uninterested and unwilling and can therefore diverge from this.
I have since learned, via helpful Twitter replies (as in, genuinely informative!), that the term is used in public health settings to delineate the gay men who are unusually promiscuous or risk-taking. That may be! This though seems like a different use. A euphemism for something pretty much unrelated.
Is adventurousness, in the sense I mean, bisexuality? No—bisexuality is a sexual orientation. It might be willingness to bend the rules of ones monosexual orientation, i.e. a straight woman being game to have another woman in the bedroom or signalling along those lines by making out with another woman at a party. And a sexually adventurous straight woman will do this. It is assumed.
(It wasn’t always thus. See: Blanche Devereaux. At least as of where I’m at in Season 5.)
There is no corresponding expectation that a man, to prove he is not a prude, to demonstrate that he does not have a Rated G inner life, have sex with men or even gesture at the possibility. This is not to say that men never gesture at such possibilities within a hetero context, i.e. because women are in some way into it. (See Marie Le Conte’s 2022 column on Harry Styles.) But no one hears that a man wouldn’t want a penis other than his own anywhere near him and thinks, wow, that man sure doesn’t like sex very much. Something to contemplate.
This gets to another point about adventurousness which is that it is different from desire. To want kinky or unusual things, or even a lot of different people. To be adventurous is to be up for trying things for its own sake, maybe to please a partner, maybe to live up to some idea you have in your mind of the sort of person you are, maybe some mix (i.e. your reputation). Or maybe it is about enjoyment of adventure itself! Aka something assumed of men and not of women, even outside a sexual realm.
Having sexual interests and pursuing them irl is not sexual adventurousness. It is just a part of human behavior, its own spectrum, but something else. Adventurous is about adventure, about trying despite having, at most, vague curiosity. The adventurousness could awaken a genuine interest but it need not do so.
Sexual adventurousness, in the sense I mean, is a straight-women thing. It is related to ideas about amenability. About desire vs desirability and all that. More later but like I said, I had to get something down on this!
This is maybe just what you are saying, but I think the presumption here is that women are "sexual gatekeepers" such that a woman is likely living at or close to the frontiers of her personal adventuresness (or perhaps is pressured to go beyond it by a partner). Mens' experiences are more likely to be limited by a factor other than their personal adverturesness.
My girlfriend slightly disagrees; her take is that a man can be "sexually adventurous", we just mean something different by it when we apply it to a man. A man into domming doesn't count as sexually adventurous because he's doing the expected thing, but a man who is into subbing does count.
I would add only that the men who are most committed to the view that women hate sex (are objects and not subjects of desire, are 'gatekeepers' of sex, put up with it on sufferance, and so on) are usually the biggest prudes, whatever their porn search histories.