If you become intimately involved with this person on a long-term basis, the relationship may be rather difficult, even intense and frustrating; but in the long run, it should also push you to transform in the way that you need to transform. You've been moving along a particular path of individual growth for some time now -- lifetimes, in fact -- as has your partner. But their deeper, more intense emotions, the ones that push them to transform themselves in some profound way, could have an inhibiting effect on your own personal evolution.
You could even get so caught up in your partner's quest for change within themselves that you simply neglect your own path and goals. Doing so wouldn't be a good idea, however; but you will find that, the more lost you become in your partner's push for personal transformation, the clearer it will become to you that your own path is quite different from theirs. Ultimately, being involved with them may push you in the direction in which you need to go, even if that happens in an upsetting way.