Maybe put on the breaks on a bit. You don't really know that what's happening isn't just an extension of transference you had in the therapy. And you need time to process what it means to lose the therapeutic relationship. Therapeutic relationships can mean a great deal and they are very personal, hence just starting with a new therapist won't replace what you had with this T. And you have to understand that once you are in the romantic relationship she can't look after you the way she did as your therapist--it will be forever different--and you might need more time to accept that than you think. Maybe take a break, spend a few months apart. Try and go on a date with someone else. Tell her you need the time. If she is really a worth while partner she should understand and respect this. It is a really big deal to change the relationship in this way, and there is real potential for harm. You should be allowed to have the time to really think about it. Also depending on the laws where you are if you tell the new T about this relationship, they may have to report her. You might want to look into this.