I suppose it depends on the individual. Intimacy is difficult if not impossible with a partner, so if it is intimacy you seek, Trigeminal Neuralgia will certainly get in the way.
As to the question of difficulty in finding a partner, I don't know. I was fortunate that my wife has remained my staunchest supporter through all the ups and downs of this journey. Maintaining relationship has not been easy; in fact, it has required even more hard work than traditional views of marital practice reveal.
Communication is a major factor. Always let the other person know about your condition; let them know that you need space to be afflicted by it and that there is nothing that they can do for you except be there and offer encouragement, support, and love. Keep them informed of any progress or relapse so that they can help and be sources of information for your physician(s). Be up front about having this rare disease because it can scare a potential partner as well as one that you might already have. Learn to trust the wisdom of your partner, especially if they have prior experience with this disease. Educate them if they do not know what it is or how to offer support.