Do you remember how your favorite relationships started? Business, personal, or whatever, you felt mutual attraction to work together, play together, or whatever. Something about the other person made you want to interact with them.
Do you remember how your relationships ended? Sometimes you or they change and you lose interest. No problem. Often you want to keep the relationship yet it ends unhappily.
Many people blame differences you couldn’t overcome. I suggest the key point in those cases is not the differences but your inability to overcome them.
No two people agree on everything. Every pair of people have differences. I suggest the key to making relationships last is not finding people you agree with perfectly. That doesn’t exist. Nor avoiding problems. You can’t predict when they’ll come up. I suggest it’s resolving problems when they come up. You can’t avoid them. The question is how you handle them.
If you can’t handle conflict, your relationships will inevitably deteriorate. You’ll be stuck with a relationship in a worse state than usual.

If you know how to handle conflict, you’ll see worsened states as inevitable but not final. You can see the relationship like a bone that sets stronger after a break than it was originally.

Why would a relationship be stronger after a conflict? The different values were there before the conflict, which only revealed them. After you learn how to handle the disagreement, you have less chance of something catching you unaware.
It also seems inevitable that your partner will feel attraction to others—a competitor in business, another person in personal relationships. Passion works like that. That other attraction, no matter how strong at first, will eventually hit conflict too. If you resolved conflicts with your partner better than your competition, when that other passion fades to regular attraction, as it inevitably will, and conflict arises, as it inevitably will, your partner will increasingly remember you.
So learn to resolve conflict!
I would start with learning to make people feel understood (not the same as understanding them!) and negotiation.