We have been in the LS for about a year and a half. Play almost completely together, although she has played solo when I was down due to surgery, and I have a hell pass but have never used it.
My wife enjoys chat and texting. She has some pretty steamy chats with playmates. At first she told me about every single chat, and I read most of them. As time went on, I read them less as she told me about them, so she told me about them less. But I knew she still was chatting.
However, she does not delete them and I am free to check them out anytime. In fact she sometimes wants me to check out some steamy ones just for the fun of it. Sometimes she will tosses me her phone and tell me so-and-so want to get together, so I will read the text to get the details, which also includes some sexy chat at times. I might read some of the others that are unrelated, it turns me on a bit.
I don't feel the need to check them out for the purpose of keeping tabs on her. I trust her completely, if I didn't we wouldn't be in the LS. Nothing she has ever written gives me even the slightest concern, it is sexual, and that is what we are in this for to begin with.
Besides, I am pretty sure that if I needed to be concerned about something I would know from a number of other ways long before I saw it in a chat.
I suppose one could seize upon "I haven't felt that way in I don't know how long... " but in fact I understand that and have felt it too. Every time we start up with a new couple it has a "new and exciting feeling" that is different. I feel the same, but after time that goes away. It's more indicative of dating than anything more serious.
Are there things she could write that would concern me? Certainly, but like I said, I would probably would have already realized there was a problem between US long before I ever saw a text about it.
What would concern me in your situation is what ClosetSwinger pointed out. I would not be happy at all, and would be concerned, if she were deleting text or chats or hiding them from me. That would certainly throw up red flags.
But for us, as long as we are both open and honest, and the chats/text do not stray off into emotional spaces I am perfectly fine with her sexy chats. I hope she enjoys them. After all, she is having sex with the guy, so why should sexy chat bother me?