Unconditional love to me is not something that can be described easily.
( Even though I truly enjoy other people`s descriptions.)
Its something you only know when, through trial, error, and pain, you come to a realization, that your love doesn`t die when harships happen.
It doesn`t mean you put up with that persons crap or abuse if it comes down to something like that. In that case maybe you only love them from afar.
Unconditional love does seem to be person specific. You can`t tell yourself, or force yourself to feel it, or command it to show up when you 'want' it.
It`s either there, or it`s not.
The great thing about being poly, is we don`t have to force ourselves to stop loving someone, if we can`t be with them. You learn to love from afar, and carry on investing in new loves elsewhere.