From what you describe, you don't kill your lover out of anger, but more as a part of a sacrificial love ritual with spiritual overtones. He wants to make babies, which are often symbolic in romance dreams for a young, growing relationship. Here's a link to the definition of a baby in a dream:
dreamdoctor.com/dream-dictionary/definitions/baby.html
In your love-making, you reach deep within him and "grab hold of his heart," a symbol of your desire to "hold his heart in your hand." He professes his love and you kiss and then his body "disappears." You describe it as if he has died in your dream. Death is a common symbol in dreams for transition and change. See:
dreamdoctor.com/dream-dictionary/definitions/death.html
A reasonable interpretation is that you want (or are ready for) your relationship to transition to a new level... perhaps even a spiritual one as his body disappears, as if it has "risen."
If that's how you feel about him in waking life (in love), embrace the symbolic and more poetic interpretation because it fits. His pulsating heart in your hand is a metaphor. That's how close you want to feel to him... and he is clearly all right with it in the dream. So, even though your dream probably strikes you as bit over the top, if not gross... congratulations just might be in order.