Your best play at this point, really your only play as I see it, is to go dark. Yeah, you've got a text hanging out there awaiting a response - you can see that through. Then disappear. Change your phone number so that no more texts come in. She can reach you though an intermediary unless she wants to work on the marriage.
If you get a response to your text, just matter of factly tell your wife that you want your marriage and are willing to give it a go if she is. If she's not willing, then inform her that you cannot have any more contact with her this way- its too hard for you and you need to move on. That's it.
To be frank with you, I'm pessimistic that she will return, but there is a small chance. So far she has drifted further and further away. I'm sure she is getting closer and closer to whoever is replacing you at this point. Every negative interaction with you (and in her book, they are all negative) only convinces her more that she's making the right choice in leaving. Your only hope is to leave her with whatever positive impressions and memories of you that she has left, without continuing to create more sadness and negativity for her to remember.
Let her live her life without you there to receive her texts and pay her bills. Let whoever she is seeing attempt to do this. Hope that he can't or won't. In the meantime, continue to make yourself healthy. Know that there may be another woman someday, when you least expect it, that will look at you with love in her eyes. Carry yourself with your head high.
