I think what others have said applies - love is dependent on the person who is feeling it.
To me, it's not only seeing it in a person's eyes, it's the feeling of being stable and safe..security. Now, for me -that's not about the financial, money aspect - it's knowing that even if for some reason the two of us were living in a box behind Wal-mart, in his arms is where I would be secure and looking into his eyes, I would feel that and know I was protected.
It's also the kindness in someone, the willingness to be there and be a true partner...and stick it out when things get rough, to work together through it.
I see that every day with my parents...they have been married for almost 60 years and my Mom jumps when the phone rings and runs to it when my Dad is gone answering it with "Hey Baby"...They randomly dance when songs come on the radio and the look on my Mom's face with my Dad's arms around her...that's what it means to me.
I also agree with whomever said that women (although I think it's people, not just women) who vomit out "I love you" so easily these days. It should be more revered.
I'm sorry for your loss of your loved one...that's a tragedy no-one should have to go through.