Sometimes, it’s a choice you make. Sometimes you choose to let someone into your heart, even when it’s hard; even if it hurts. Sometimes you choose to share your life, both the good and bad, rather than try to live it alone. A partner can make things easier to handle, even if it’s just to love and support you. But you have to let them in. You can’t let fear keep you from feeling.
On the other hand, I guess you can. But you shouldn’t. You miss a lot that way.