I'll answer why I went for MLC over WW in my case. I suspected WW. I've checked & checked & checked. I have full access to computer, phone records, have seen her FB, e-mail, phone. Not a trace. And, she is not that good at the technological side to hide her tracks. I've stopped doing this, but for a long time, I'd snoop.
She also never displayed the kind of behavior you see from someone in an A. She wasn't being secretive. She stayed attentive to the kids. She doesn't show that kind of obsessive quality. She doesn't even do a good job at keeping her phone on or where she can hear it to pounce on calls or texts from an OM/W.
She also has been letting herself go a bit. She still exercises sporadically, but she's been putting on a little weight. And she is voluntarily asking for more nights w/ the kids, which I doubt she'd do if she were in an R.
So the symptoms of MLC were there, but I finally got really tired of looking for evidence when it was always a dead cold trail.
She has been in IC this whole time, & I know that her IC would be warning her off any R. She has also expressed that she needs to find herself and just wants to be alone for now. I know we can't trust their words, but this is done w/ sincerity (she's never been a liar & wouldn't be god at it) and fits with all the other evidence.
Now, I'm prepared that w/ an MLC, an A at any time is a high probability, so I wouldn't be surprised if she did in the right circumstances. There are some real signs that after a year & a half she may be emerging from the MLC (perhaps into just mild depression), so maybe I'll dodge that bullet.
Anyway, I've tended to expect that there was an OM that was part of the factor in all of this. I've known at least mild MLC all along, but I was sure that she'd jump on the infidelity wagon. So, I haven't chosen one conclusion over the other. I chose both, and only after a long time of scrutiny have I at least for now concluded she's not a WW.
Just my case though.
Me: 50 W:43 S6, S3 M: 12 yrs. T: 17 M is bad & Not happy Bomb Mar '14 S 5 Feb '15 D Bomb 13 Apr '15 (but "no hurry") DB Coach May '15 Wants proceed on D Aug '15 Starting 1-on-1 negotiations Sept '15