This quote is from Perfect Love, Imperfect Relationships. I have found this to be a really valuable book. John Welwood is a great teacher, able to combine Buddhist wisdom and techniques with Western psychology in a way that makes sense and feels useful (unlike Mark Epstein, who is nearly as popular).
When love or passion flows unobstructedly, it is experienced as bliss. And when we awaken to the bliss in our veins, its natural outflow is radiant love.
Of course, in our creaturely vulnerability, there is no way to avoid loss and separation from what we love. We cannot avoid coming back again and again to the experience of being alone. No one can finally get inside our skin and share our experience -- the nuances that we alone feel, the changes that we alone are going through, the death that we alone must die. Nonetheless, loss, separation, and this fundamental aloneness are important teachers, for they force us to take up residence in the only real home we have -- the naked presence of the heart, which no external loss can destroy.
Standing in this, our true ground, is the ultimate healing balm for the ache of separation and the wound of love. "You must fall in love with the one inside your heart," says the teacher Poonja. "Then you will see that it has always been there, but that you have wanted something else. To taste bliss, forget all other tastes and taste the wine served within." The warmth and openness at our core is the most intimate beloved who is always present, and into whose arms we can let go at last.