The unholiness was lain on Jesus' flesh and soul, not His spirit where His divinity exists. This is why He could show us that His fleshly will must be submitted to the Fathers will, and that His fleshly will may be different from His Fathers will. Never once did He act out on His fleshly will, there fore He was legitimately tempted in all points, yet remained sinless.
The three only ever existing persons -- Father, Son and Holy Spirit -- have a loving relationship that we won't know the intensity of until we are in heaven.
Regarding your comments on Jesus...
Well said. It certainly is a fine line, and it took hundreds of years for the Church Fathers to really define the relationship between the Father and the Son, as well as Jesus' divine and human natures. Stray ever so slightly and we venture into heresy.
We cannot imagine what God has in store for us, but we will partake in the divine nature somehow, according to Peter. We only see as in a mirror now (mirrors 2000 years ago weren't like ours now!) The only thing that we could even come close to seeing an image of this love is the love that exists between husband and wife (in an ideal, selfless relationship) - this relationship being fruitful that it even can produce another being - a child. And such is the Trinity - the Love of the Father and the Son for each other eternally produces the Holy Spirit. Lots to contemplate there!
Regards