Sadly, there is no privacy, and you can't expect people not to notice that you are suddenly taller.
If you are going to do a LL surgery, you should not be ashamed about it. You have to admit it.
How can you get married and not tell your wife? You cannot start a relationship with deception.
Nah brah. You clearly have no experience with this surgery.
To OP and anyone else who is reading, please don't listen to this clueless guy.
First, there is plenty of privacy around CLL. You have protection under the law (HIPAA) for your medical records to be kept private and don't need to disclose anything to anyone about the surgery. Also, most people aren't very sensitive to height and can't tell for sure that you got taller. Almost everyone you know cares and notices way less about you than you think they do. At most they might notice that you "look different" or "look better" or "got skinnier" but the thought of possibly becoming taller won't even cross their mind. Personally, I only had a few cases where people were even remotely suspicious about my height change and it was very easy for me to shut it down before it became an issue. I'm extremely confident that absolutely no one IRL knows that I did CLL.
Second, if you are going to do a LL surgery, you shouldn't be ashamed of keeping it a secret. You don't have to admit anything to anyone that you don't want to. Don't let others tell you how you should feel about the surgery or who you should tell. If you want to keep it a secret you 100% have the right to and most people who have actually done the surgery would absolutely support that decision. While there are certainly people who tell their families everything, plenty of others have barriers for some things that they don't want to cross. Don't let others decide what you're comfortable with disclosing. Personally, I have a great relationship with my immediate family and yet I don't feel any need to tell them that I did CLL.
Finally, get married when you want and tell your future wife whatever you feel like telling her. Personally, I've dated several girls and slept with dozens more since I got CLL and I didn't tell a single one and I will never tell anyone that I did CLL. What's considered "deception" in your view or "cheating" in the view of OP's shrink, are just people with a limited worldview trying to hold others to their own set of morals. If she's getting a guy with a height (and everything else) that's she's clearly okay with, then why does it matter how he got there? Women do plenty of things to make themselves more attractive to guys, and what's considered attractive doesn't even stay the same over time.
Heck, millions of guys wear shoe lifts to dates and exaggerate their height to try and pass the threshold; at least the CLL guy is actually taller. There's nothing tricky about it. It's hard enough to find someone you're mutually attracted to in this day and age and most marriages will end in divorce anyway. If you find a woman that you actually want to marry then don't let some random judgmental person tell you what you should or shouldn't disclose to her.