Smith had sex with wives of other men. That is adultery under any standard; not just polygamy.
~”Smith had sex with wives of other men. That is adultery under any standard; not just polygamy.”~
Smith was -sealed- to wives of other men. (And it is fundamental to this discussion to understand the difference between sealing and marriage.) It’s not clear to me as to why; but there were purely dynastic arrangements made in some cases. Whether or not there was sexual intimacy between Smith and wives of other men is not substantiated by reliable evidence. We have a few secondhand accounts and claims, but no more.
The question then becomes, if there is no sexual intimacy in the relationship, is it adultery?