Together you'll establish both love and friendship, and you'll give each other a lot of freedom to move around and be yourselves. There will be a real openness in the ways you express your affection for and attraction to each other. Jealousy and possessiveness aren't likely to affect your bond, because neither of you will want to engage in petty, controlling behaviors with your lover.
You'll both understand that your lover isn't 'yours'; you don't own each other, and you can't dictate your partner's feelings or behavior. If you're in one another's lives, it will only be to bring each other pleasure and happiness. This relationship may or may not last long-term, and this influence in itself won't add to the stability of your connection. But one thing is certain: If you can allow this affair to follow its own course without trying to control it too much, it will lead you places you never expected to go -- and the ride will be a lot of fun. Don't let yourselves be bound too closely by tradition, convention or others' expectations. It's up to you to define the boundaries of your relationship and determine how this bond plays out in your lives.