Yitro contains 16 mitzvos according to Rambam. Most of them are linked to the 10 commandments but notably one commandment is missing: adultery.
Instead he learns this prohibition from Acharei Mot:
Mitzvah #160: Not to have sexual relations with someone else's wife Lev. 18:20
So, then what does he learn from the commandment in Yitro?