I understand "letting go," Angel. It still doesn't mean you drop your own personal boundaries. I'll give you just one example, from my own experience:
Even after I decided to file for DIVORCE from my wife, when she refused to end her affair (talk about "letting go" -- this was the ULTIMATE "letting go"), I still would not tolerate her talking to (or texting) her OM in front of me, or our kids, nor calling him from our marital home. She respected the boundary.
Did it "affect" me when she did that? Well, sure, but only to the extent that it made ME feel like crap that I would allow MYSELF (or my kids) to be treated so disrespectfully. I had already given up feeling personal sadness over it, or any illusions of "winning her back" -- I was done.
I just chafe when I see the "controlling" word thrown around these forums so loosely and, often, incorrectly. "You're too controlling!" is often nothing more than the rant of a wayward spouse, crying "I don't want to have any consequences for my poor behavior!" No, you cannot control another person, but you can ABSOLUTELY control how they treat US.