I kicked my mom out of my wedding — she did a shocking, unforgivable thing

She brought the “something old.”

A groom’s mother crossed an unspeakable line by bringing her son’s ex-girlfriend as her plus-one on the day of his wedding, insisting that they should get back together as true “soulmates.”

The cringe-worthy tale, posted to Reddit recently by the 30-year-old man, revealed that the newlywed’s mother “never really liked” his 29-year-old wife, June.

“The main [reason] being the fact that June didn’t let my mom push her around. She kept firm boundaries, which I really admired, and she even helped me do the same,” he wrote.

“My mom hated this, calling June controlling and wishing I hadn’t broken up with my previous girlfriend Margo, who my mom loved,” he recalled. “I was with Margo for 5 years and it was horrible.”

My ‘practicing witch’ daughter eloped and planned a Halloween wedding party — her mom’s reaction was too much

He described Margo as being “very controlling and manipulative” and as someone who used lots of guilt to push him into things he wasn’t on board with. It was only from supportive friends and his sister that he found the courage to leave her.

While the man admitted that his “life has improved since,” that wasn’t good enough for mommy dearest, despite her keeping a strong poker face — until the nuptials.

“When June and I announced our engagement my mom didn’t freak out, which was weird considering my mom hates June,” he added, noting that his parents split after college and were given respective plus ones to the big day.

Of course, he assumed that invitation to the small ceremony of close loved ones would go to their spouses.

I’m an etiquette expert — congratulating a couple on their engagement is rude, here’s what to say instead

“After the ceremony, me and June went to take pictures and then met back with everyone we invited to the reception which was pretty big,” he wrote.

“When we got there, my sister and June’s best friend/maid of honor ran up to us in a panic. Before they even said anything I spotted it. My mom was at the table with my dad, my dad’s wife, and Margo.”

The well-composed bride kept her new hubby calm, but he still took drastic action during the heated moment.

“I walked over, pulled them both aside, and simply told them to leave,” the groom claimed.

“My mom tried to explain Margo and I are soulmates and June is just in the way of true love, but I wasn’t hearing it. I didn’t care.”

CLICK HERE TO SIGN UP FOR OUR MORNING REPORT NEWSLETTER

While the man put things out of his mind in the short term, upon returning from their honeymoon he was inundated with “hundreds of texts from multiple family members.”

“Some think I could have just ignored Margo and didn’t have to ‘freak out’,” he said.

“A few others, including my dad, think I should have just kicked Margo and let my mom stay but after the stunt my mom pulled, I didn’t want her there either.”

And, while the groom began to “second-guess himself,” readers rallied in his corner.

“Why is it you are expected to keep peace when your mom disrespected you and your wife on your wedding day?” one person wrote.

“She was cruel in her comments about your wife. That warrants NO CONTACT,” wrote another.

“The reason the mother liked Margo is because she and Margo are so alike. She sees June as a threat to her control,” added a third.

For the latest in lifestyle, top headlines, breaking news and more, visit nypost.com/lifestyle/