Is that embedded in the Commerce Clause?
No. However it is can be a relatively simple exercise to determine what are NOT among the Privileges and Immunities of A4:S2:C1 or the 9th Amendment’s other rights retained by simply determining what was illegal in any of the several States that Ratified the Constitution or the Amendment.
Homosexual activities are not covered by either of these clauses, being illegal in various States that Ratified them.
Such activities should have remained unlawful under State laws for their own Jurisdictions and federal Laws for places like the Territories not under the jurisdiction of any State.
Some things just need oppressing.