Your heart is the very center of your energetic and physical bodies. It's the gateway between the states of subconscious surviving (contraction), or consciously creating (expansion). Your autonomic nervous system wires a pattern between your heart and brain each time you experience emotional pain, and unless you reprogram it, you will continue to unconsciously limit the amount of love, joy, and abundance in your life.
You cannot be a little pregnant, and your heart can't be a little open. You are either in a state of expansion or contraction.
Find out how open your heart is on an average day. Even highly spiritual people are surprised with their results! Knowledge is power.