I'm going to apologize in advance. I know my reply will be long, but I hope it helps in some way.
I'm a BW...but also a BGF in two relationships following my D. My M lasted almost 22 years. And like the two of you, we have five children together. The age span of my children at the time of divorce was 2-17. Like your BW, I gave it time. Five years actually. And when it never improved, that's when I ended it.
I know none of us really know each other on here, so when we give advice, so much of it comes from our own personal experience. Please know everything I write here, I fully realize your BW may not be experiencing. But just maybe she's feeling like I felt, and am still feeling in my new broken relationship, and possibly it applies.
I appreciate your defense of your BW, with regards to the conditions of your separation. I agree with you. The way I see it, as a mom of five children, following through with a D is the LAST thing I'd have time for. The two of you separated. But in all honesty you left her first with the affairs and betrayals (and it sounds like you truly understand this). So when she decided she couldn't take it any more and she left you, that ended all commitments between the two of you. The actual legal part of it is just a paper thing. Nothing more.
Today, she's living her life as that single woman...with a LOT of children. She didn't want you to leave her, and she certainly didn't want to be a single mom raising your children without you by her side. It sounds like maybe she's doing what she can to survive. She sees herself as the single woman you made her....the problem is no matter how much she meets other men, talks with them, and lives that single life...she still loves you, and can't replace you.
She didn't choose this. You did. And it's so damn hard to switch gears with regards to relationships, when you have five little ones running around reminding you of the life you once had and worked so hard for. I was so very torn. I hated my WH for what he did. I was crushed by what he did...and he too was a complete and utter ass after DD.
I remember days where I lay in a heap on the floor beside my bed, hiding and crying...sometimes in my closet, so my children couldn't see or hear me. I'd have to turn it completely off so I could come out and prepare dinner, smile at their homework, and play with them during sports and scouts. I became very skilled at acting. Once I left him, I took very stupid risks. I'd go walking down by the neighborhood lake, late at night, when I couldn't sleep. I'd drive way too fast, alone, late at night, with the music blaring. I would get together with friends and drink too much, because it seems that's what it would take to turn off the painful thoughts and the feeling like I wasn't good enough. Looking back, I know what I was doing... I had given up on the life I had worked for, the one I loved. And for some crazy ass reason I couldn't see there was another life, different, but far better than that crap, just waiting past all this shit.
I'm going to go against the grain when I say wait on filing for a D. If neither of you has filed yet, and neither is pushing for it... then wait. What is it hurting? I do think your BW may benefit from an IC, but that's for her to say...and unfortunately they aren't cheap. I know at the time I couldn't afford one, nor did having the five kids allow me a chance to see one. Have you told her you'd do whatever it took for her to get to one, if she wanted it? I know you're both living as single people now, but something is keeping her from cutting that last string. I can tell you I held on for many reasons. Money. Insurance. Five children. Zero time. My children were the only career I knew. Fear. Shame. Insecurities. And love. Once all the others were taken care of, I realized the love was completely gone, and I moved on.
As for the other guys your BW is bringing into her life...you're right in that she's single now and can do that. But it also sounds like she's still in love with you. No matter how much she takes care of what I mentioned above, she can't shake how she feels about you. To me, that's a good sign.
It doesn't sound like she's dealing with what you've done. And honestly, I don't blame her. After reading your profile, you've put her through so very much... and for so darn long. How can she cope and be the mom she needs to be??? My heart goes out to her, because I've been in her shoes. The difference is I didn't have a WH fighting for me. If you feel like you can and will be the man she deserves, than don't give up hope.
As for being angry over what you saw in her phone...yep, can completely understand that. Of course you're going to be hurt and upset. Maybe even left with feeling like your heart was ripped out. But as you said, you created the situation. So what do you do??? Honestly, it doesn't hurt for us to see how much we can still affect our wayward partner (even an ex). I don't think it's good to do something intentionally to hurt each other, but that's not what happened here. It was an honest case of she did nothing wrong (IMHO), and you snooped, found something, and it crushed you. You both learned something that night... She let her walls down (unfortunately with alcohol) and couldn't stop with the flow of emotions for you...and you learned how much you couldn't bear to see her with another.
I still think you both have a chance. The only way you'll ever know is with time, and her opening that door. I hate seeing this because I can so surely feel her pain. Don't give up hope unless you feel like it's completely gone. Sit down and write her a letter. Explain how you felt when you held her that night, and how it felt to see what you saw in her phone. TALK in your letter. Spill your guts. If it's a good letter, she will read it a number of times. You can't rehear a conversation, but you can always reread words on a paper.
I hope things go better for the two of you....please keep us posted.