Yup.
If anyone believes love is something that is static and unchanging they are dead wrong. As John Lennon said "Love is a flower" that you have to tend and nourish.
But that IS unconditional love though, isn't it? Meaning "I'm willing to do whatever it takes to make this relationship (be it marriage, child, dog, etc) continue because I love this person" - BUT if the other person doesn't feel that way, that's not your problem. The love exists for you and even if you choose to leave that relationship (or the other person chooses for you), that doesn't mean you don't love that person any less. It just means that you realize that that person doesn't value the relationship (or life, in the case of a murderer) as much as you do, so you are making the choice to leave - or having the choice made for you.
I guess it really boils down to your personal definition of unconditional love. I have been in 2 past relationships where I can honestly say that I still love the person I left. Leaving was INCREDIBLY hard, and I still love them to pieces - but they were both unwilling to grow and change with the relationship, so I would argue that they didn't love ME. I was giving and giving and giving, and they were doing all the taking. They were in the relationship for convenience - I was in it for love. If they had also been in it for love, they would have been willing to compromise and adapt WITH me, as I was willing to do so with THEM.
And once I realized that, it was much easier to finally find a healthy and loving (unconditionally, on both sides) relationship. Now, if one of us goes crazy and decides to cheat or run away (or heaven forbid, kill someone), I'm sure that will split us apart in many ways, but the love we had together will still be there.
Plus, we have a child together, and if you are mentally healthy and willing to love each other unconditionally (even if your wife is throwing a fit for no reason - ha!) that goes a LONG way toward strengthening a relationship and moving it toward the unconditional kind - at least in my mind