Upgrade, why would YOU move out of your home if SHE is the one having an affair? If I were you, I would stay put. Tell her to move out if she wants to.
When you confront, don't ASK her if she's seeing anyone else. She'll say no. Instead, TELL her "I know that you're having an affair with ______ (fill in OM's name)." It's like the example in DR. You don't ask a kid if he took a cookie from the cookie jar. You tell him that you KNOW darn well he took that cookie.
If you want more intel, the next best place to look is in her email. If you don't have her passwords, you can install a keylogger onto her computer which will capture every email and IM she types. Is she taking a laptop with her on her trip? If so, I'd install a keylogger before she leaves.
Again, different people have different opinions on snooping. You need to have a very strong stomach to go down this road, because the things you find will only hurt you. It all comes down to what YOU need to do for your own sanity. I was so sick and tired of my W telling me that I was paranoid that I had to get proof of her A. Once I did, I was finally able to detach.
Once you gather enough intel and confront your W, you should store away everything you found and then stop snooping. Gather, confront, and then detach and move on. If your W wants to come back and work on reconciling, that's great. If not, there's nothing you can do to make her come back. All you can do at that point is focus on making yourself a better man and re-building your life into something great.
Me: 33 WAW/MLC: 33 M: 4+, T: 10+ Separated: Nov 08 A#1: Oct 08 - Jan 09 (exposed and ended) A#2: Feb 09 - ? 1: http://tinyurl.com/mrmistakes 2: http://tinyurl.com/ckch9t 3: http://tinyurl.com/stillwaters3