Common mistake made by a lot of people.

"Assuming that the person who ends a romantic relationship/long lasting friendship will be doomed to bad luck".

One thing they forget/don't know is, "they might be the problem themselves".

If I am the problem in my own relationship/friendship, anyone leaving me won't be doomed to bad luck.

No one will ever be doomed to bad luck by avoiding problems or by solving problems.

If you can't solve it, then get rid of it, stop tolerating problems that remain unresolved for the sake of being in friendship or relationship.

One of the main aims of friendship is to share happiness and not to be used and abused in that friendship.