Love could be considered selfish if you believe that human survival itself is selfish. I am not sure existence and wanting to be alive is selfish? All species would by default be selfish by mere existence and consuming air/resources.

But then again there are many different theories/opinions for human existence/ species evolution. How that relates to love, well love is a social aspect and yes connections and relationships keep us alive. So if the assumption is equating alive = selfish, then yes love is selfish. But if not, then I'd say it's not always selfish.