Just found this great quote that fits your situation, "If your approval of your child is predicated on their beliefs, you don't love your child at all, you love your beliefs."
If you extend yourself that you want to maintain a relationship with your family at some point, but they hold to their JW enforced doctrine, trot that quote out to them. It's not you that caused this division, it's their beliefs that did, always remember that.
If you have trouble realizing that, just ask yourself how many people of other backgrounds get basically disowned by their family for simply having a boyfriend? You'll only find overbearing beliefs/religions/cults to blame for this kind of attitude.
Stay strong.