Recently, I was told by someone that atheists are incapable of experiencing all the intricacies of love because a large portion of love is spiritual. Also, since we do not believe we exist eternally or in an eternal god, therefore, we cannot believe in eternal love, and without a belief in eternal love, our love is inferior.
Then I was told that I was lying when I said that I have experienced deep and abiding love as a religious person and also now as an atheist and that they are qualitatively and quantitatively the same.
Now, there are many different types of love: brotherly love, compassion for those that hurt, romantic love for a partner, a parent's love for a child, etc. And the experience of these loves can illicit a wide array of emotions: a feeling of safety, a yearning in the heart, a melting of the heart, a passion to want to be swallowed up in each other, an obsession in thought of the other, a sense of caring and concern, heartbreak and sorrow when you are apart, wanting the best for the other person, valuing their happiness, wanting to be near physically and emotionally, admiration, gratitude, peace, comfort, warmth, etc.
If my love for my wife changed at all as I went from theist to atheist, it got better and stronger. When I was a theist, I put God first, then myself and my wife. But, when I came to believe that god does not exist, my wife became the most important person to me (there is no god or anything else above her).
Secondly, once the universe is devoid of gods, angels, and the spirits of the dead, one suddenly values more deeply one's fellow travelers. We are all that we've got. Imagine how you typically feel towards the strangers on your airplane, when you think of yourself as being surrounded my millions of people. But, consider how your feeling towards those strangers would change if your plane went down on an isolated island in the South Pacific and only some of you survived. You become everything to each other. That is how I feel now that I believe we only have this one short life to live and you are my fellow travelers in a universe mostly devoid of sympathetic life.
Thirdly, my purpose in life was to do the will of my Father in Heaven when I was a theist. When I lost belief in god, I lost that purpose for my life as well. When I asked myself what was the point of living if nothing eternally mattered, I realized that although things don't matter universally (i.e., the universe doesn't care what I do), they do matter locally in space and time.* My wife cares whether I live or die, and also our families, and to a lesser extent, my friends/co-workers and associates. I can still touch people's lives for the better and it will matter to them. And what I do my influence a few generations after I'm gone. So, as you can see, my whole being has become wrapped up in others, and as such my love and concern and compassion for them have increased.
*There's a story I would like to share with you that illustrates how what we do can matter on a local level even though they don't matter on a universal level. It was inspired by the writing of Loren Eiseley.
Once upon a time, there was a wise man, much like Eiseley himself, who used to go to the ocean to do his writing. He had the habit of walking along the beach before he began his work. One day he was walking along the shore; as he looked down the beach, he saw a human figure moving like a dancer. He smiled to himself to think of someone who would dance to the day, so he began to walk faster to catch up. As he got closer, he saw that it was a young man and the young man wasn't dancing, but instead, he was reaching down to the shore, picking up something and very gently throwing it into the ocean.
As he got closer he called out, "Good morning! What are you doing?" The young man paused, looked up and replied, "Throwing Starfish into the ocean."
"I guess I should have asked; why are you throwing Starfish into the ocean?"
"The sun is up and the tide is going out and if I don't throw them in they'll die."
"But young man, don't you realize that there are miles and miles of beach and Starfish all along it, you can't possibly make a difference!"
The young man listened politely, then bent down, picked up another Starfish and threw it into the sea, past the breaking waves. "It made a difference for that one."