There is this concept in the Universe called a Twin Flame. This is a single flame put into two different souls. They spend many lifetimes trying to find each other, and when they do sparks often fly and it usually only works in one of their last lifetimes on earth.
What makes this different from a soul mate is a soul mate can be a sibling, friend, lover, or really anyone, a Twin Flame is always romantic.
I can attest that for me the concept is real and I have found my Twin Flame in Patricia Sunshine.