Okay, I don't actually believe you would be okay with this, I just think you aren't comprehending the issue here
Case in point, you seem to have a few things confused.
I never said couple don't have issues? Of course they do, everyone does at some of their life, and I do think talking thinks out with friends/family outside the relationship if fine too, as long at it done respectfully to the person you are talking about, I wouldn't tell people anything about my husband that I know he would be embarrassed to share, or private things he would prefer me not to share, that isn't because he is forcing me to keep quiet, it's because I choose to keep it between us, I respect him and I respect our relationship, and I would never break his trust in that way.
OP isn't controlling who he sees or what he says, she never has, so where have you got that from? She has been absolutely fine with him meeting up with his friend, although quietly disappointed he's making time for her but not for OP, she has let him get on with it, they've been friends for decades with no problems or interference from OP, until she started to suspect something more was going on and asked if he was telling the OW personal details about their relationship (which he denied), so it led to her uncovering the nature of their messages.
It really doesn't matter what YOUR boundaries are in YOUR relationship, as this isn't about you, OP has clear boundaries about what she would not be comfortable with him sharing with people (intimate details of their sex life), and he has broken that trust, not only broken that trust but talks about her as if he couldn't care less about her, as if her grief and problems mean nothing to him and she is just there as someone to pleasure him, except now she is broken and he doesn't want a wife like that. He is disrespecting her and disrespecting their relationship by saying all that behind her back, yet pretending to OP that they are fine and are working on their marital issue together as a team.
If you can honestly say that you would be happy with your husband who lied about your relationship and talked about you in such a disrespectful manner, while flirting and going on coffee dates with another single woman, telling her one thing behind your back while telling you another thing to your face then okay, but I still don't believe it.