I see your point, but I have to disagree. Just to be clear, I am not a fan of NTR (unless we are talking about Netori). I personally don't care about a girl having had sexual experiences before, nor mind that she mentions it occasionally, as long as stays faithful to me from now on.
The only thing Caroline did so far which bothered me, was when she went out clubbing, specifically to find a date. Because this was in the present and not the past.
Other than that though, every time Caroline mentions her exes, she does nothing except praise her brother for being so much better than any of them. "Nobody ever made me feel like this" or "nobody has ever made me cum twice before" or "none of my exes were able to make me climax from oral sex".
I find it weird, how you can have a girl constantly praise you for your performance in bed and you still find a way to take it as an insult to your honor. At least in my eyes.