I love Maika's interpretation.....and I couldn't agree more! I don't think you should validate how she feels, b/c that's the keyhole she wants to pull you through and work you over.
The only response I think you should give is something like the following: (words in parenthesis are not for her)
"The past several weeks (or however long sleeping in separate beds has lasted) has been difficult for me. You don't want to be with me in an intimate relationship, but you act as if you expect the benefits of my attentiveness, companionship, and accountability. Over the period of our marriage, your selfishness and demanding ways have become increasingly worse, and your sense of entitlement is intolerable. It was not my intentions to ever upset up, but I am not without feelings myself. I had hoped you would eventually realize that marriage is a two-way street of showing appreciation and honor. However, the constant lack of respect you have shown to me is unacceptable, and I've had enough. Neither of us seem to be in a good place at the moment, and I don't think it would be wise to continue further phone communication while you are gone. I plan to take the rest of this time apart to do some very serious thinking about what I want in my future. I suggest you do the same. Just understand that in a separation, you forfeit the right to ask me anything about my personal life, or receive the same benefits that come in a loving marriage relationship. How you feel about me not being straightforward, or accusing me of lying, is too ironic for words. Please do not contact me except for a real emergency".
So, it's wordy.....and maybe too much for a text message. Can you email her? Maybe you can shorten it or reword it more effectively......and sound like you (only not mushy and validating). It needs to be sent all in the same body of text, and no room for a back & forth conversation. You have to avoid a discussion by not giving her a chance to reply before you have your say. And so not respond, b/c she's going to send a blazing text......if she's not in a state of shock. Anyway, I think it's time to make a stand or don't respond at all.. Is it too harsh? No! Is it tough? Yes! And you had better stick to NC for the rest of her time away......or it will lose the effectiveness. I think she'll try everything in the book until she sees you aren't playing and she can't manipulate you with her different shanigans.
I realize this will take courage, but I think you've got the right stuff. You will have time away from her intrusions to plan how to handle things when she gets home. It will give her time to get over her tantrum and may actually start looking at how badly she's treated you (well, that may be expecting too much from her).
If you send what I've written above, it will be like prepping for the confrontation when she gets home........if you still plan to approach her about OM. And if you are ever going to, it has to be as soon as she returns home, IMHO.
I'm sure some other LBS will say you need to validate her feelings, and shouldn't tell her you don't care, etc. But I disagree, b/c this gal needs to have a serious wake up call, and know this is not all about HER! She is telling you all about how upset she is as a manipulation to make you go crawling to her.
Anyway, you can decide to send it, or not respond at all. I don't want to pressure you. This is your life, not mine. It's your decision to make, and you live with the results (good or bad).
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!