A woman is refusing to postpone her wedding just so her mom can attend her sister's first childbirth.

On Reddit, the bride revealed her mom suggested the bride push back her wedding date so she could attend her other daughter's first childbirth instead. Making matters more complicated, the two sisters are on bad terms because the pregnant sister cheated with the bride's ex-boyfriend.

"Long story short, the father of her child is my ex boyfriend — whom she was sleeping with while we were dating. So we don't have a relationship with one another," the bride-to-be wrote via Reddit.

READ MORE: Woman Finds Out Cheating Husband Isn’t Father of Her Sister’s Baby

"I'm finally getting married in two months' time after a year of planning and everything has been going to plan so far with no hiccups. That was until my mother called me earlier in the week to ask me to postpone my wedding by at least a month," she continued.

The bride's estranged sister is due to give birth on July 17, and she requested their mom spend the entire month of July since the "due date is just an estimate."

However, the bride isn't willing to postpone her nuptials, so she gave her mom an ultimatum: "She just simply needed to choose who she wanted to support."

"She's been fence-sitting and that's why we're here. She says I'm forcing her to make an impossible decision and my aunts are also trying to convince me to postpone. Don't get me wrong, I know she's also mom's child and wants her there for her but I also want her there for me and I've already waited a year for this and everything is already planned," the bride concluded.

READ MORE: Bride's Sister-in-Law Insists She Change Inconvenient Wedding Date

Users in the Reddit comments section offered their support to the bride.

"Your wedding is on a particular date. She can either make it or not. You have a venue and vendors and your spouse's entire side lined up. Your sister wants you to inconvenience ALL OF THEM in order to have your mother with her FOR 'AT LEAST A MONTH'? Don't make me laugh. Your sister and her issues sound like they could fill a psychologists' convention for a month," one person wrote.

"Feels like a power play by your sister. This could have been asked [six] months ago when it wouldn’t have been such a big deal. I’m sure she can cope for one day without mom," another commented.

"Don’t for a second even consider postponing. Sounds like your sister is devoted to ruining everything in your life that she can. That seems like a deep rooted psychological problem or just pure evil. Your mother can make her own decision. You don’t specify how she reacted to your sister’s betrayal. But you should celebrate your happy marriage with people who want to be there for you," someone else weighed in.

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