To explain what moderator 42 wrote:
The Shulchan Aruch and the Rama both pasken that derivative (i.e. lower-level sins of the same category) sins of the “big three” are also yehoreg v’al yaavor, even though those sins are of lesser severity.
Because the Shulchan Aruch and the Rama also pasken that negiah derech chiba is asur min HaTorah, like the Rambam, from the same posuk that forbids relations with a Nida, it follows that this issur is a derivative of Arayos which would be yehoreg v’al yaavor. The Shulchan Aruch is explicit that negiah derech chiba is yehoreg v’al yaavor by Nida (which is the issur of Arayos that applies to all non-married, adult, Jewish women). And there is no reason to think that negiah would be more meikel with respect to Eishes Ish.