You're likely to recognize this person at a deeply instinctive level, even if your 'recognition' of them is vague, based on a long-forgotten past-life image that was imprinted indelibly on your soul. This invisible bond is no less compelling for its nebulousness, and in fact it comes from someplace real, though now unreachable: that ethereal past-life connection that you share, which has brought you together in this life to tend to some unfinished business. In some way, it is still your karmic destiny to help this person become more subtly in tune with their true, core self -- to learn to connect with themselves in a compassionate, even spiritual way.
You can help to teach them this self-compassion simply by being yourself, but if you can focus on this goal -- the growth of your partner's soul, and of your own -- you'll make even greater progress. The bond you'll share will be quite emotional, just as it was in a past life; the emotional strength of your connection hasn't faded over time, and you can use that strength of connection to build a solid bond in this life if you both desire it. Use your intuitive connection to communicate at a level that doesn't require words.