I'm sorry man, but I don't think you can believe a word she says. It's almost a certainty that sex was involved, likely multiple times. I know that's hard to hear, and even harder to accept, but you've got to come to terms with that to even begin moving forward.
If she wants the pain to end, or at least subside, you need the truth. The whole truth. Only then can you begin to process whats happened amd make informed decisions. I think she's in serious damage control mode right now and will say anything, no matter how untrue, to save her own ass. Make no mistake, you've been traumatized.
I've seen it said often that infidelity hits harder and hurts worse than the death of a loved one. That was the case with me. This stuff hurts. Bad. My whole world was shattered and I couldn't tell what was real and what wasn't. Continued lies, trickle truth, and changing stories are only going to prolong and intensify the pain. You need an entire truthful timeline of events. Who, where, when, what, how many times, what was said, what was felt at the time, etc. How much detail you want as far as physical activities is up to you. Some of us want to know all of the dirty details, and some don't, but the rest is necessary if there's to be any type of closure.
If you can, have her read the book "How To Help Your Spouse Heal From Your Affair" by Linda McDonald. It's a fairly short read, but packed with useful advice and will let her know where your head's at right now. It really opened my wife's eyes. The audio version is about 2½ hours long, and we listened to it together. I think that was the first step in getting my wife to understand just how devastating her actions really were.
You need to take care of yourself. Make sure you're eating enough and getting enough sleep. I know that's easier said than done, but drink protein shakes if your appetite is shot. You need your strength and wits about you. See a Dr and get some temporary meds if you need some help with sleep.
Sorry you've found yourself here man. Most of us know what you're going through right now, tho, and there's a good group of folks here that can offer advice and just listen if you need to vent. Your wife needs to come completely clean and start showing some signs of honesty and contrition. Right now she isn't giving you anything to work with.
[This message edited by Pogre at 3:20 PM, Monday, January 26th]