I play WoW, and I have several friends who also play WoW, mostly casually, or raids slotted around work schedules. But my other friends (most of whom play video games) are either totally indifferent/ignorant/uninterested in the game, or they have quit/refuse to play it on irritatingly smug moral grounds that they have not succumbed to the "popular." I don't raid because my work schedule simply doesn't allow it, but I have a serious idea of the time commitment you enter once you have gotten geared up.
When my last roommate and I, who was also a best friend, lived together, he and I would often talk to one another over skype or vent even though we were in the same house, because we didn't want to move our computers and bottom line: were really lazy. We did this even when we weren't playing WoW. It is not the same solution as being able to talk face to face, but it did give a more connected feeling than yelling at one another through the apartment or trying to figure out if someone was having a conversation with someone else. Also, it didn't require both of us to be playing WoW. That isn't really a solution for all the time or even to save communication in a marriage, but at least it would be clearer sometimes that you were having a conversation With Her. If her guild isn't comfortable with you, who probably is not a guildmember having access to vent, there is always skype or some other thing that could be your own private channel when you are both doing things at different computers.
Now, I have another idea for you. Use WoW to your advantage. In her WoW calendar, with her consent and help, schedule days and times where she pulls some weight around the house, like dishes, or cooking, or laundry, or all the other mundane garbage that someone has to do--hopefully as a team when there is more than just one person living in the house--so that you don't get frustrated right as she's grinding through Naxx for the 40th billion time. AND so things get DONE before raiding that don't involve Alchemy or the Auction House. This way, with them in the WoW calendar, she can see her WoW Raiding schedule AND her House Raid schedule. You can point out that if she needs to up her professions and fishing, she can schedule doing stuff around the house around the amount of time she wants to spend on those things too. Like throw a load of wash in and fish for awhile in a tourney and when the wash is ready to be switched to the dryer, she can work on whatever needs doing for Tailoring, etc. until it's done in the dryer. She doesn't sound like she's Achievements crazy, but you could always make them part of the theme for doing stuff around the house if she is with small rewards built in to your week and budget like going out to eat, or a movie on a non Raid night--but seriously that should happen anyways with or without things getting done around the house being hinged on it. You are adults after all. Also, the two of you should sit and look at the WoW alarm clock/timer controls on this one. Just check them out. If having a clock tell her to take a break is something she can use (I don't know because everyone's personality is different) then it is worth looking into. Work WITH her to manage her WoW time and her IRL time, using the danged game with either time management mods that independent people have developed or with the new stuff that's been added by Blizzard themselves.
And seriously, seriously, plan a real vacation like everyone's been saying! Budget for it, pick a place you both want to go where you both agree not to take ANY electronics with you, talk to your work and get it all arranged so you have some time to look forward to. That way she can also plan with her guild (This game is seriously like a second job, I know) and they will know not to count on her for that week or two week period.
I don't think you should have to join the game, especially if there is pressure for you to grind your way up to 80 and start raiding with her. There is a lot to do and enjoy in WoW that don't involve seeing all hardcore end game content and the chores that come with it like gear and rep and all the rest. I took ages and ages to level up to 70, and got there just before Wrath came out, and I'm still taking my time, despite leveling being even easier to do. Everyone plays this game differently and the beauty of it is that you CAN play this game a lot of different ways. But if people are out there, who want you to play, and want you to play so they can play with you THEIR way, I don't think that's very fun or appealing. And I know very well that people who are in a certain groove of playing WoW can be very resistant to just goofing off in the game and enjoying it for what it is--a game. My advice: Stay out of the game unless you can play it however you want, no strings attached.
Good luck with IRL Raid management!