Unless you're a member of the royal family, who have a history of inviting their exes to their nuptials, it can be quite odd and awkward to have your former flame watch you marry another person.
However, in some rare instances, a former (or current) love interest doesn't even need an invitation, they can show up on their own volition if they really want to make your day miserable.
This week, a video that first surfaced a few months ago is once again going viral after people on social media can't get enough of a scorned mistress crashing her secret lover's wedding.
The couple was in the middle of their ceremony when a kerfuffle at one end of the aisle interrupted the special moment.
Turns out, it was the groom's disgruntled side chick that was causing the big scene.
Dressed in a wedding dress, complete with a veil and gloves, the visibly upset woman confronts the philandering groom. He then tries to persuade her to leave the venue but without success.
At one point, the mistress attempts to speak to the clearly shocked bride, but she remains impressively calm throughout the chaos.
A bridesmaid finally steps in and tries to escort the woman away from the couple, but what happens next remains a mystery as the video cuts out.
It remains unclear whether or not the couple, who are reportedly from South Africa, ended up getting married after the messy encounter, but one thing is clear - the internet has a lot of strong feelings and questions about the situation.
Some sided with the mistress, arguing that the man misled her by not telling her he had another woman. Others applauded the bride for staying composed, but none dared stand up for the cheating groom.