A couple of tips:
1. I agree with Matt re: "fatty" foods. OP prob meant just junk food/cheese/ramen noodles, but just in case, you NEED some fat, like nut butters, avocados, olive oil. I'm a "raw before 4" person (usually, and completely ignoring coffee/tea in my equation), and I can't imagine pulling this off on a mostly fat-free diet.
2. Have some non-junk junk food available. My go-tos when I need sugar but don't want to go on a cookie binge are dates and figs. They're pricey, but they're both fruits (dried), dates especially have lots of natural sugar that should hit the part of your brain that is used to an evening jolt of sugar from alcohol or dessert. Don't go crazy with them, but I'm a guy who will crush a bag of cookies in one sitting, so 4 dates and a couple of figs is a massive improvement when I think I'm about to lose it.
3. In general, have lots of ready-to eat food handy, or make sure to prepare a bunch of food in advance. The biggest challenges will come when you are tired and/or emotionally drained, and you will have no desire to make a fancy salad. Hummus and veggies (carrots, peppers, tomatoes, in the Middle East they also use sliced onion) is one of my "I am cranky and want to binge but still be healthy" safe havens.
4. Expect to spend some money. Fresh fruit, veggies, prepped hummus, etc all cost, and you may be hit with a wee bit of sticker shock. But then remind yourself how much money you blow on alcohol and take-out. I've been mostly healthy most of my adult life, but I still have a wee mental block about spending $8 on a green juice, yet think nothing of dropping $100 at the pub.
5. You need activities to distract you when you are jonesing for some sugar. A lot of our bad habits are literally, just habits. You need to replace them with something else. Since you're doing this challenge with your wife, I assume you two can find suitable alternative activities.
But plan it in advance, almost like a contract. "Honey, after din when I want some beer, we need to do ... instead."
I'd recommend BEFORE you start, prepping some great soups and freezing them, so you can pull them out mid-week. Also have more or less your whole 2 week menu planned out, cuz if you ain't used to eating like this, you may find the emotional drain of trying to be "perfect" is as tough as the actual eating part.
Also BEFORE you start, depending on your caffeine intake, you will need to taper off of it. Going cold turkey can be really hard, the headaches can be brutal. I'd actually recommend you get off of caffeine before you begin the actual cleanse.