WTF am I doing?

You can all check my (40M) history for the full story, although it's not that salacious. The TL;DR is that almost a year ago I found out my wife (37F, married 15+ years, no kids) was having a physical affair (probably not the first). We went back and forth for months, she continued her relationship, and nothing really changed. Since late October we have simply been living together and have not had a physical relationship, with her leaving for days at a time to be with the OM. I typically spend my Thursdays through Saturdays alone (sometimes longer) since I am not seeing anyone outside our marriage. Back in February I got the flu really bad - she couldn't have been bothered to even help me out and get me some 7Up and saltines from the store.

I have been in contact with a lawyer, although I have not pulled the trigger. Why? I don't know. It's just hard to do. Part of me doesn't want to deal with the hassle of a divorce. I said I wouldn't do anything like file for divorce without talking with her first and hearing what she has to say. It's not surprising that she hasn't talked to me about stuff at all, even though I really have nothing to say, it's all about her. So, whatever, I have issues and we simply continue on like roommates.

However, I'm to a point where this non-movement is just grating on me. I don't want to be in just some holding pattern forever. So last night I asked to talk with her. After dinner and some TV we (shockingly) didn't get around to it. I walked into the bedroom and she was texting someone and when I walked into view she non-discretely closed the phone down. Whatever, not surprising, but it was a little odd considering the stuff she knows I know. So I checked our phone records sigh. She wasn't texting the OM, she was texting one of her old high school boyfriends. So now she's stringing along another man? I know that she's always had a thing for him (man #3), I'm not sure if she just pines for him or has rose-colored glasses about their short relationship almost 20 years ago.

This has finally just gone too far. But I can't help wondering what is stopping me from just getting this thing done and over with.