Is Upapada Lagna the default indicator of a future spouse?
Because nowadays people can have many serious relationships.
So for example, if a person has 1 serious relationship with one person and gets married to another person. Does UL denote the 1st relationship and UL1, which is 8 places away from UL becomes the actual marriage?

Or we must not mix relationships and marriage?
So do we use Upapada Lagna (UL), UL1, and UL2 in actual marriage and divorce cases only? If so for serious relationships, are there any techniques?

Thanks in advance.