My wife had a ~6month long affair, after ~15 years together. While we were core renovating our just bought home and despite having three kids. I found out the hard way, not because she confessed it openly. We had no money problems (due to my work), we always talked about everything. Life was somewhat stressful (due to the house renovation in addition to my full job and kids) but fine. I had developed feelings for a friend once, talked about it with my wife, she wanted to stay monogamous. She didn't return that behavior years later with her affair.

In counseling and long talks, we found that I could not have done anything different. She's sorry. And while I often think of leaving her, I won't break up the family for my kids - still seems like the best option, ~2 years later (if I take their mental health into account and am not only considering myself).

It's a cliché, but "knowing" things and "living through" things are very, very different:

* Never give yourself up in a relationship or a job

* Never risk everything you have (I couldn't divorce her even if I wanted, without having to pay exorbitant monthly payments)

* You can do everything right and it still can go wrong

* Just because you give everything doesn't mean others will behave the same towards you

"Knowing" these things is different than "living through" them. The affair broke my mental model of the world as a whole. I thought: no matter how bad it is, I can influence my very tiny happy bubble in a distopian world, and giving everything to the right people (who also give a lot back) will make them honor our common code of behavior.

Now, I trust a lot less. I don't waste time on relationships I don't get as much out as I put in (no matter if acquaintances, friends or business related), I secure myself a lot more (prenup, letters-of-intends, etc.).

I'm still miles away of not being depressed and feeling broken, or being able to concentrate or being creative again (which means I'm still unable to work effectively for more than a few hours a day). And the model of the world I have in my head now does not feel like something I want to live in, but it's still - slowly but steadily - changing for the better. Getting here took an enormous amount of effort: Being unable to work at all for about a year, being physically unable to stand, just breaking down in public or in front of clients, amnesia (there are weeks of my life I simply can't remember, whole vacations during the depression that are just gone). It took psycho-therapy, clinical stays, (re)learning habits and techniques to get me out of bad places...

This is not a call for sympathy, but please do learn from me (I made a throwaway account to keep my anonymity).

TLDR: My point is:

* Take care of yourself and don't trust others unbounded. Ensure the "what ifs" don't cost you too much (e.g. prenup, letters-of-intend, ...).

* Happiness is a choice for the most part. Enjoy life and the moment while you can. Sometimes it's little things, sometimes it's big things. But notice them as much as you can.

* There's different levels of honesty - think good about which one you choose. Honesty leads to vulnerability and some people will misuse it.

* Stay positive and give first in relationships, but always listen cautiously to your gut - if it tells you that you are giving too much and receiving too little, reconsider and react. fast.

* Keep friendships and hobbies you enjoy alive - despite family, job and relationship. Friendships are built on common experiences (not common interests!), and the older you get, the less chances for new common experiences with new people you'll have. Hobbies and things you enjoy are as important. If shit hits the fan hard, friends and having routines to recharge your battery are the things that can save your life and get you out of the hole.