In a Spanish village in 1954, Julia (the protagonist) is set to marry Miguel (the son of a sergeant). However, on their wedding night, Miguel discovers that his new wife is not a virgin; consequently, Julia’s father decides to kill Gabriel, Julia’s former partner and current lover. Gabriel’s murder sends shockwaves through the village, forcing Julia to leave in the company of her mother—whom she hates.

1)too long, shoot for 25-45 words and only one sentence.
2) it would be unclear who the protag was if you didn't say so, but still shouldn't be there and the line needs to make it clear. I read it five times and thought Miguel? The Father? Gabriel? because she seems to have no part in it except lost virginity.
3) are they set to be married or are they married (it seems this is on the wedding night)?
4) former partner makes gab sound like a business associate, and current lover seems awkward given that she's getting married.... unless she's pregnant and trying to cover it.
SUGGESTION:
When the groom discovers his wife's lack of virginity on the night of their wedding, he sparks a brutal honor killing by her father, causing her to flee 1950s Spain with her estranged mother.

This could be read as a summation of the entire plot including the denouement; that is, she's forced into exile, doomed to live with a mother she hates.

End of story, fade to black, roll the credits.

But one of the rules for writing a logline is: don't give away the ending. So another reading is that the information given is the setup and inciting incident for the rest of the plot. If so, what is the plot that arises from these circumstances? That is, what becomes the protagonist's objective goal after her lover is killed and she is driven into exile?

In other words, this logline seems to gives away too much information about the plot as a whole--or not enough. Please clarify.

Also, the protagonist appears to be passive victim of other people's actions. Not initially: I presume she's a willing partner in the premarital affair. But that seems to be in the backstory that is only revealed on the wedding night. After that reveal, she's portrayed as a victim of other people. Where is her agency in all this? In what way does she assert herself, take control of her life, her destiny by committing (to repeat) to an objective goal despite all the adversity, all the consequences of her premarital affair?