@Cecilia
Relationships is a lot about personal experience and taste. It's about getting to know about yourself and how you can figure out what kind of person you want to be together with. It's best not to actively search for someone or to cling to someone, but to rather let things happen as they develop. Forcing it could make you and/or the person you want to be with feel trapped, which eventually in most cases end up in separation.
It is also best to be yourself, and to be together with someone who isn't afraid to be themselves. It will be extremely tiring and so-not-worth it if you or your (potential) partner end up trying to be someone they're not. This too in most cases will end up in separation.
With so much things that can go wrong, it may seem silly to continue a quest to find your eventual partner, if anything. But see failures more as a way to learn rather than failures. Most people don't learn form their mistakes and thus in each new relationship tend to make the same -or similar- mistakes. Sure it can be aggravating to have one relationship after another fail, and it's totally ok if someone decides they are just not meant to be together with someone or if they are better off alone. As long as they are happy with their choice.
I can go on and on, but I think I summarised all my thoughts reasonably tidied up ^^
That is what advice I can give to you
I hope this helps.