1. that people are perfect. We all mess up. Forgive and more importantly move on.
2. that your partner will always be the same. People change over time, and so will you.
3. that your love will always be the same. It changes over time

Married 26 years here. The biggest mistake I see my single friends make is getting in relationships with the wrong women. Beauty probably should not be a top five criteria. I am not saying you need to date hags, but for a successful relationship personality, interests, and compatibility matters much more.

Find someone that values and prioritizes the same things you do. Someone that you can communicate with and trust.

Beauty is a depreciating asset. If the only reason you are with someone is because she is hot or good in bed, then you are in for a bad time in the long run.

Why are you asking me? I've been married for 17 years, clearly I'm doing things right. If I was in the business of making mistakes, I wouldn't have been married this long. All kidding aside, I often see people have a lack of interest in the other person. It should be genuine interest in the other person's hobbies and interests. Like, my wife is really into dog training, I'm not, but still we talk about it and we do it together sometimes, just because I want to share in what she is doing and support her in it.

Taking their partner for granted and letting communication get lazy. Yes you’re friends and partners, but it can be easy to forget the emotionality and connection in the routine bustle of life.

Become a feminist. It doesn’t mean you kowtow to every whim and women are always right and better than you. It means you take your fair share of running the household and the relationship.

Read this; https://amp.theguardian.com/world/2017/may/26/gender-wars-household-chores-comic

Learn about the Second Shift and Mental Load. Together, make a job board of things that need to be done around the house and divvy up work.

If one partner knows how to do a housekeeping task, they other should know too.

My wife doesn’t brag about me to her friends because when her friends brag about their husbands it’s insanely basic shit. For example one had Covid and was bragging about how her husband learned how to make eggs for the kids so she could get a little extra sleep in the morning. Eggs! Look, if you don’t know how to cook eggs, you don’t know how to cook. It’s a life skill, not a wife skill. Not saying you need to be the family cook, break down household chores however works best for you, but be prepared to take over any and all chores from your spouse at the drop of a hat. You never know when sickness might happen, or worse. What would you do if you suddenly became a single parent if only for a week? Know how to do it all now so you can take it on when you need to.

NEVER STOP DATING.

Kids or no. Continue with date nights. Planning dates.

If you stop being a couple, you stop being a family.

The health of your relationship as a couple is crucial to the stability of the family.

FYI, perfection not required. Share your failures. It is demonstrably human.

Not a man, I’m an enby, but I’ve been married to my wife for 15 years.

Showing a woman love often means shutting up, listening, and empathizing. Not fixing.

Don't do dumb stuff. This concludes my TED talk.

Expectations need to be well established before marriage. Don't expect your wife to do anything she want not doing before unless you talked about it before hand.

Don't stop talking. Never assume you and your spouse have said everything there is to say on everything.

If you want them to be your life partner, then treat them as such.

Don't lie and admit your mistakes

Don't ask me - I'm still busy making them.

Don't stop dating once you move in. They shouldn't stop either. Plan nights out, random gifts, and movie nights together. You're not roommates, you're partners.

This one might be controversial, but if you have ex's "you're still friends with" no you're not. Early in the relationship people will say, "Oh, that's cool. I don't mind." Because you're in the honeymoon phase, but it's just all around awkward for everyone.

Don't change or get into too much effort to get the woman. Because it will need that same effort to keep her. That will wear you out and she'll divorce you after years because "you've changed", while you slowly became yourself again.

Sure you can spoil her, but don't do it the entire time you're chasing her. She will think you're "that kind of person" when your spoiling is unsustainable.

I mean, it's the secret to getting a relationship and staying in one. You need to have open communication and treat your SO as an equal partying life.

Too many men don't see their partners as equals. They want to be dominant or are just in it for sex. These do not make for a happy life.

Try not to marry someone who's going to break up with your sorry ass.

Don't get married. I was married for 5 years, had 3 kids, but it didn't work out. My girlfriend had been married twice before I met her and neither marriage lasted a whole year. We've been together for over 28 years now. Sometimes you have to learn what you don't like in order to find who you're compatible with. In our case I think it's the idea that if you're married you have a tendency to take the other person for granted. If you're just "shacked up" you can leave whenever you want (of course having kids and co-ownership of property may complicate that equation).