Depends on how you define it. The theming around Black Widow is really heavily gendered — obviously there's the whole "Widow" thing, but when you dig deeper into that, a lot of her stories have themes of self-liberation, commodification, etc that are very female-coded.
And I mean, if you go off of her original origin and aesthetic, a nation tricking a woman into service by faking her husband's death, and then who goes onto be defined by the "Widow's Curse" (having everyone who gets close to her end up dead, because, get it, she's a widow), that's a little less novel in the modern age than the Silver/Early Bronze Ages, and especially less so if it's a man and not a woman.
Still, there are a couple of candidates for "male equivalent." The first one people think of is Red Guardian, Black Widow's husband whose death was faked to force her into service. But the similarities stop at "dead husband" being the inversion of "Widow" and their both having been forced into costumed service for the USSR.
Brubaker then came up with the idea that there were male trials for the Black Widow procedure, and that the youth-extending Black Widow chemical somehow turns men insane. Which is was clever because it explained why Black Widows were all women, and why the men that have stayed in Natasha's life for several decades all seem to have gone crazy and evil (e.g. her surrogate father Ivan, and the original Red Guardian). Brubaker introduced Niko Constantin (pic related) as the single best result of the male Wolf Spider trials, but it's still hard to judge whether he "counts" as a male Black Widow. He's the closest thing to it, though.