Braking Your Heart So That It Isn't Broken

For the past few days, I've been having an unusual thought: Be safe with your heart. Protect it. The reason I call this unusual is because my normal philosophy is to give my heart away freely. This thought has even made it beyond my brain and ended up as advice to others and I'm doubly confused on how such a life operating philosophy could be coming from my mouth. Have you ever been in a situation where you're trying to protect your heart? It's hard stuff. The heart wants what the heart wants and no amount of reasoning can usually convince it otherwise.

How do you put the brakes on your heart?