This relationship could get serious fast, because your lover relates closely to you and strongly identifies with your family and past on an emotional level. The natural intimacy between you makes you really comfortable with each other from the start, and if your lover meets your parents or siblings, or even your best friends, they feel an immediate affinity for them and vice versa, as if this person is the missing piece of the group! It's likely that they feel immediately accepted into your inner circle; if they encounter any problems of resistance from family or friends to the relationship, it is probably just token opposition and quickly fades away.
They're emotionally sensitive to you as well, knowing just what you need to feel secure and well-loved, and it is rare that they hurt your feelings. Needless to say, this kind of aspect definitely supports a lot of love and understanding between you that translates well to the long-term! If you have made or end up making a commitment to this person, you can expect that your family and close friends are an integral part of your relationship with each other. And starting your own family together isn't out of the question, if things move in that direction.