Well, I'm not sure anybody could pinpoint that spell's source solely by description. However, reconstructing the spell from the ground up is more than doable.
I think we can safely say that it's probably a Candle spell in shape. ;)
What exactly is the intention of this spell, to begin with?
Being "bound for eternity, mind, body, and soul" sounds nice and flowery, but it's very vague.
Are you trying to combine energies on a soul-deep level? Consecrate a relationship, to keep it together?
Connect the two of your fates as one?
The exact nature of the bond changes things.
What exactly do you want to accomplish with your spell?