Your story sounds almost the same as mine right down to the timeline and events.
Only differences are my Wife, who is from Tokyo Japan (I am a Canadian guy) and she is a Capricorn. About two years ago she became agressive, even physically agresive. We also have a child together ad now she is gone for 4 weeks, same story as you in that there is no reply to communications. I didn't lose my temper, but te day she left I had reached my tolerance and said some words that pushed her away. I didn't understand that, and maybe this is the case with your girl, that she became onely even though we were there. Maybe we missed that their actions were because of feeling lonely, hurt, stressed, or other things we didn't see or understand. Then some other guy comes along, does not live in the situation and looks like a Knight that saves her and she gets sucked in. Not saying this is the case with your girl, is with mine though.
How can we win them back? When they are gone, are they really gone? As hard as it is, the pain can be so deep, so intense and the days can feel like weeks, It seems that when they are gone they are gone, how do we deal with it? They have dealt with it in their own way, and maybe moved on, how do we cope, deal with that? It's hard, especially after five years, but somehow we need to move on also, as hard as that heart wrenching process is we need to move on, but first, maybe send her a mail, about what you have learned about her that you did not understand before, what was missing, what was not right maybe, and let her know that as hard as it is, you respect her wishes and feelings to be where she is right now, but that your Love is there, and that you would do al you can to work at making it right, maybe even a relationship counselor if she agreed. Please understand, as I hae had had too these past weeks, that sometimes their hearts turn cold, they can shut us out more than we can, and if they do there are many and long standing issues that cause this, as guys we really don't and can't see or understand until after we get shaken up in the worst way. We can't change a persons feelings, but if they have anything left we can try to reach them as best we can, but also need to know when to set them free, as the expression goes, that is the hardest thing ever to do anywhere anytime as te deep cutting pain each day feels like an eternity. For myself, I own a business, have not been able to go in since this happened.
Anyways, not able to write well these days, just wanted to comment because it sounded close to my situation. Hope I did not make it worse, but we have to face reality, with the tears and cutting it does. Reach out to others, talk, cry, pray for help, strength, do all you can to keep active. Hope an wish you well.