This relationship could be huge, definitely for your lover, as it inspires a transformation in them that lasts their whole life; but for you as well, because it signifies the breaking of some old, negative karmic bonds from a long-ago past life. You're finally freed to graduate to the next level of your soul's evolution, so celebrate! You two were involved in a past life, and it wasn't a good relationship.
You might have been lovers, but it's more likely that you were adversaries of some kind -- warriors from opposing clans, or something of that nature. You were the stronger of the two of you then, and you dominated this person ruthlessly. They felt defeated by you, overwhelmed by your power and even broken down by it. In this lifetime, you get together to finally put an end to that old karmic tie that wasn't good for either of you. Instead of dominating this person in this life, you help them to become who they are. You encourage their freedom on every level, and you let them know that you want to know exactly who they are and what they want in life, and that you're there to help them achieve their goals. In being this way in each other's lives, you help each other to break out of that old, bad pattern and establish a newer, much better and more beneficial one.