Sure it is. The concept of love in our society is a restricted one due to social ethics morals , etc. There is a concept called "Polyamory"
http://en.wikipedia.org/wiki/Polyamory where people openly admit to loving more than one person, and have multiple parallel relationships with different levels (primary, secondary...) or non hierarchical approaches.
Plus, open relationships and non-monogamous arrrangements have been around since centuries.
There are many different love styles , too. John Alan Lee has found about 6 different ways of lovestyles, and I assume you can love different people in different ways. Problem is the ability to be legit about these things, since we live in a society that enforces "heteronormativity"http://en.wikipedia.org/wiki/Heteronormativity by moral and legal codes and sanctionizes aberrative behaviour as "sick". In specific terms relating to loving more than one person this means "mono heteronormativity"
http://books.google.ch/books?id=8Y49...tivity&f=false