"Poly" is Greek for "many"; but Greek for romantic love is "eros". "Amor" is a Latin root. A more fiddly linguist would have coined the term polyerotics (Greek) or multiamory (Latin).
Likewise, "hex" is Greek for "six"; but the Greek root for ten is "deka". "Decimal" is Latin. In this case, more consistent coinages would have been either hexadecadic/deca-hexadic (Greek) or sexadecimal (Latin).
Interestingly, in both cases, at least one of consistent formations (polyerotics*, sexadecimal) is more sexually suggestive to the modern English speaker than the hybrid coinage. Coincidence?
*Actually, "polyerotic" seems to have been adopted by online polyamorist communities as a designation for specifically sexual polyamorous relationships. This is OK, I suppose, although I think the Greeks had it right that romantic love and sexual desire (which they denoted with the same word) cannot be cleanly cleaved in two.