In union, this mādana-bhāva might take extraordinary forms, whose manifold manifestations are particularly visible in the nitya-līlā. The workings of mādana are incomprehensible to Cupid himself, and it would be impossible for even the Muni to describe them. (UN 14.225-226)Madanasyeva. Vishwanath first glosses mādanasyeva, which seems unlikely to me. A possibility is madanasyaiva, which is what Jiva seems to be interpreting, even while reading iva. If we accept the madanasyeva reading, then what appears to be said is that Prema and Kama are different, but that both share a certain ineffable quailty.
Muni is glossed as both Bharata and Shukadeva (Vishwanath says either, Jiva only Shuka, Vishnudas goes for Bharata). I would think Bharata was intended, as he is considered the ultimate authority on the sthāyi-bhāvas. But the nitya-līlā is not described by Shukadeva, either, so either appear to be a reasonable possibility.
Vishwanath seems to have an alternate reading here, but does not gloss, so no way of ascertaining what it was. Perhaps madanasyaiva, since he here glosses madana as Krishna himself.