You can be because love is not narrow but broad and inclusive.
Of course “true” in the sense of being true or faithful to one’s true love partner in marriage is spiritually correct and psychologically ideal. But this is not exactly the same as true love.
True love does not simply mean that there is one special person in a given life that you are destined to be with, though that is sometimes true. But the phrase should really be “true loves” and not just “true love.” Real love is lavish and radiates out to the whole world. As the brilliant sociologist Erich Fromm wrote in his book The Art of Loving:
“If I truly love one person I love all persons, I love the world, I love life. If I can say to somebody else, ‘I love you,’ I must be able to say, ‘I love in you everybody, I love through you the world…”
Love is “true” not simply because it is faithful to one other person—love is true because it is real and comes from the soul. So yes, you can love more than person—you can love many and it will be true love if real. It is a matter of degree, intensity, and karmic relationship.