Trying to revive this community. What are your best advice for a health long-term relationships in your 30s?

I have a few things I've learned over the years.

You don't have to agree with something for it to be true. As everyone else has been saying in this thread, communication is key. There will come a time when your partner gives you some feedback that you don't agree with. That doesn't mean their feelings on the matter are untrue. They may be "wrong" but arguing over their interpretation of your actions isn't productive. Acknowledge their feelings, and accept the feedback for what it is, an attempt to communicate and problem solve.

Also, don't go to bed angry. You don't have to solve every argument before sleep, but at the very least, acknowledge the issue is unresolved, and it should be deferred to the following day. Staying up late arguing is counterproductive, and leads to a shit day the next day.

This one may be a touchy subject for some, but IMO, having some level of joint finances can really smooth out the operation. At a certain point, you are not two people, but a single entity. I have met many people who have no idea about their partner's finances. I've listened to co-workers complain about their bills getting paid and certain bills being "my bill" or "their bill". The power company doesn't care who pays the bill, it just needs to get paid. Having some weird power dynamic or line in the sand over money always leads to resentment, and just seems unnecessary. You're in it together, makes sense to act like it.

From very early in our relationship, my wife and I had a joint bank account, where we pooled money to pay all the monthly bills. Originally, we came to an arrangement where we each agreed to put X amount every month from our personal accounts to cover all the monthly expenses. Over time, we ultimately combined accounts, our income goes into the joint account, and bills are automatically taken out. As a family, X comes in and Y goes. It's not relevant who makes more or less.

Not really specific to that age but communication is the most important thing in any relationship. If you have any problems with anything your partner does or doesn't do talk about it, do not let it fester and grow on the inside until it all bursts out and becomes a much bigger thing than solving that small (or even big) initial problem together would have been. And that means direct communication, no subtle hints or expectations of mind reading.

Don't date someone you are incompatible with, expectations will grow. Find someone who you share at least two hobbies with, and similar food habits.

You don't want to fall in love with someone who will love you back, love your dog, then be crushed when you refuse to take your sick dog to Reiki, feed it vegan and give it homeopathic pills, instead of real veterinarian care. Been there, it wasn't pretty.

Communication is, IMO, the most important for a meaningful relationship. I suggest reading the book "Non violent communication" by Marshal.

I would say knowing what to expect, and relaying what your partner can expect when one of you is upset. Been married 7 years, and my wife and I just had the conversation (mainly due to my becoming more self aware of my feelings) that I need to leave a situation that triggers my anger. She thought I was fucking off to Narnia for the longest time. Nope. Need to go away so I don't throttle someone.

Keep separate budgets. Keep separate checking accounts. If you live together then have a joint checking account for bills, and auto transfer your share into it on paydays. Most divorces are caused by arguments over money. You don't have to argue over money if you don't share it. There's a lot of freedom and it's really nice not having to ask to buy yourself big things. My first 2 serious relationships involved a shared checking account for everything and they were disasters. My wife and I follow the system I outlined above and we've never fought over money during our entire 20 years together, not even when we were flat broke. I make more than her, so I contribute more to the joint checking account, so that we have approximately the same amount of spending money each payday. That money is ours to do whatever we want with, and we don't need permission from each other to buy the things we want.

If you start feeling angry in a conversation - than it's best to stop the conversation (in a friendly manner) and take some time to feel the feeling and think about what's going on. Sounds kind of obvious, but it's something not easy to do - in m experience.

Listen, really listen to them. Put yourself in their position and really empathise with them. Remember and reaffirm regularly that you are a team and that you both have the others interests at heart, you should be one unit against the world.

If you get mad or argue, apologise, it doesn’t matter who is right, you’re apologising for upsetting them.

Do things together, and separately, share your experiences.

Try and eat facing each other when you can, with all the screens around it can really be easy to forget that face to face contact.

Never go to sleep with unresolved issues, don’t be afraid to be honest about why you are upset, and make them feel comfortable doing the same.