Your outlook makes it sound like you have as little effect over your own relationship as you do over the stock market.
- How do you argue? Is your partner denigrating? That’s a personality trait and an immediate no.
- Do they have an addiction? If you are married, you can try to work through it if they want to get better, but statistically it’s a long shot. But if you are just dating, why bother?
- Are they materialistic? Are they just in the relationship for what you can do for them?
- Are they honest?
Etc.
Granted, even this information gets tainted: narcissist parents, for example, might come across as their parents being nice, but them not being nice to their parents.
You can tell a lot about someone by how they treat someone they don't like. Some people get downright cruel with people they don't like, and it's a huge red flag because some day they may find reason to not like you. You're just setting yourself up to become a target once you find yourself on their bad side.
You sometimes see this when someone's hating on a public figure. They insult the person's weight, appearance, and speculate about their sexuality. I am never surprised when these people turn out to be abusers and harassers.
Trust me, if you stay married long enough, there are going to be times that you don’t like yout spouse and vice versa. That’s when you really see what you are both made of. Over time the rebound either gets faster as you learn how to disagree civilly - or worse.
I think this is also why words of affirmation and acknowledgement are so important, like taking the five seconds it takes to say you appreciate your partner, and thank you for clearing the table after dinner yesterday.
But you also need to sample across different partners. How many partners do you need to sample to evaluate whether the fights you have are on the better or worse end? Then there's only so much time in life. Also you change and get more mature. I don't think I learned that much from the relationship I had at 19 than at 25 and again at 30. Choosing one partner for life, while not impossible, is pretty flawed because you never know how both of you will change over the next 10 years. Plus the general problem with us humans that we're just never content with anything for extended periods of time. The grass is always greener on the other side of the fence. By that logic, don't even start a relationship ever. Stay single, so you don't have any responsibilities. Slightly dissatisfied with your current job? Put in your two weeks notice and see where life takes you. Shouldn't be to hard to eventually get another job in tech. Moving shouldn't be an issue at all. Unemployed for a year? No problem, you got plenty of savings, since there is no nonsense like college funds for any kifds going on in life. Only that eventually you might wonder if your life might be incomplete without having raised your own kids... That green grass stuff again...
The one thing you can be certain of is you and your partner will change. Perhaps the solution is to develop some tolerance to that change if you want a long relationship.
When you're evaluating a decision, you have partial information about the extremes. If you've been with someone for a year, you know how bad your worst fight was. Chances are though, whatever it was is a sampling from a distribution that you've only sampled a small amount of.
Your eventual worst fight will be worse, because when you have more samples chances are the extremes will be more extreme. (BTW if you're evaluating algorithmic trading strategies you need to think about this.)
If you're already thinking things are bad enough to consider leaving, you can look forward to them getting worse even if the underlying dynamics are no different.
Note the asymmetry and the importance of the extremes. Everyone who has a breakup story also had good moments and may have mostly enjoyed their average day. But you choose to leave because of the lows, not the average or the highs.