Is it ever hard? YES! Today was not a banner day in our household.
Are you ever at odds with your spouse? YES! I'd say at least three times a week before and after meetings. That is when he has the burning need to appear more saintly.
I mean particularily at holidays or birthdays for those married to JWs. YES! Negotiating what will or not be permitted at Christmas starts in about July.
Do you ever feel bad that your spouse can't attend or does your spouse ever feel bad? YES! Most difficult for both of us is locating counsel that both of us trust. We're really on our own when we get stuck. But change that sentence. It's "your spouse won't attend". Everyone has free will. When I don't attend, there's a general clucking at the hall. If I don't appear for a month or more, there's anxious pressure for hubby to drag me along. The elders are constantly on the lookout for "progress." No progress, big ca-ca.
In general what is it like? Imagine a nosy in-law times ten. This in-law will be quizzing your partner on everything up to and including your sex life. Your partner will receive lots of sympathy for her sad situation, and your absence at meetings will be tsked over. Your partner will not be completely accepted by the biddies at the hall because of her compromised state. Since the WTBTS dictates every detail of behavior, expect to see shadows of their doctrines and rules in every decision the two of you make.
Would you consider your relationship normal or strangely unique? Definitely "strangely unique". I wouldn't have considered it except my children are grown and if this doesn't work my folly is my own.