You have felt comfortable together, shared a wonderful sense of familiarity and felt like you've known each other for years right from the beginning. Except in this relationship, it could actually be less of a sign that you're so similar and in tune, and more that you're subconsciously attracted to each other because you're actually acting out an old relationship. It could be one from your past in this lifetime or it could even be that the two of you were involved in a past life, but either way, the result will be felt in this life.
If you're acting out an old relationship, even if it was a good one that gave you a lot of confidence, love and support, you're still shortchanging yourself with this person. In the beginning, even if you feel like you knew each other instantly, you don't. And even if you want to recreate something that was just so wonderful a long time ago, you should still give this person and bond a chance. You might discover that your relationship actually creates a connection that's even better than the old past life one. Do each other the service of really getting to know each other as the individuals you truly are, not the people you're projecting onto each other the way you'd project a movie onto a blank screen.