Interestingly enough, that is what my H told me when he finally said we were over a few weeks ago. That he tried to find the 'spark' but it wasn't there and I deserved to find someone whose face lit up when they saw me...
I don't have any answers for you, but I will be thinking of you! If I knew how to make 'it' come back, I wouldn't still be here...sorry.
It is a tough situation to be in. I think the butterfly feeling comes and goes in a relationship, that is just the nature of the beast. Someone once said the key to a long relationship is that you don't both fall 'out of love' at the same time. I guess that assumes you both will do so along the way from time to time?
OK I am not helping so I will jump off, but I am thinking of you and I am bummed for you, I have been rooting for you both.