That was an honest and sincere post Scott, you sound as if you've said and done all that we humans can say and do. I applaud your honesty with your wife. It's so difficult when two people have different viewpoints about what is right and what is not. I hope your wife keeps her end of the bargain and I can understand your trepidation, I know first hand how devastating it is to detach from our kids.........
As Cedar and COM have mentioned, it's important to get out of the 'usual' stuff we are engaged in with our difficult child's. My SO and I went out every single Saturday for almost 2 years, just to get out of Dodge. We went to the ocean, to the city, on long drives, long hikes, strolls through small town events, anywhere really, just to get away. It was so helpful to me. We would talk about my daughter for awhile and then let it go and enjoy the rest of the day. We planned weekend get-a-ways, often. We had dates where we would have dinner out once a week. In long term relationships, I agree that you have to ignite some fun and passion, joy and laughter, you have to make that happen. And, with a difficult child, you have to get away, out of the house, out of town. Those Saturdays have now become a regular part of our lives, we hit the road every weekend. Now that the worst is over and we're back on level ground, now it's just all fun.
It's easy to forget how to have fun, how to laugh, how to simply enjoy each others company. difficult child's suck all the air, energy, vitality and every ounce of fun out of us........I hope you and your wife can protect what you have. But, if you can't, then you're on a new path. There are casualties on this difficult child journey and relationships with our significant other, can be one of those casualties. I hope that isn't the case, but it is certainly understandable.
I wish you the best of luck Scott. You are earnest and loyal, honest, realistic and sensitive, you're a good guy and I sincerely hope it works out with your wife.