In a Reddit AITA post, the anonymous woman said she refused to feel obligated to care for her future husband if he was ill.
"This is harsh, but I hate taking care of sick people," she said in the post.
"My siblings and I were always taking care of our parents whenever they get sick, and I just hate it."
"I'm sick of it, and I hate feeling bound or obligated to take care of somebody. My life is full of moments and events like this and I just finally want to live my life to the fullest."
The woman went on to say that she and her future husband had been discussing their wedding vows, and he wanted traditional Christian vows.
"'I, [husband's name], take thee, [my name], to be my wedded wife, to have and to hold from this day forward, for better, for worse, for richer, for poorer, in sickness and in health, to love and to cherish, till death do us part,' she said, adding that hers will be "identical" but without the word sickness.
"I'm going to replace it with 'in happiness'," she said.
However, her fiancé was not impressed and is "rethinking" the marriage.
"My fiancé says that he will not accept this and he is very mad at me, he is even rethinking the whole thing," she said in the post.
"I just don't want to feel obligated to take care of anybody sick for years of my own and only life, it's so stressful and I think he is being very unreasonable right now. It's just a marriage vow and I have the choice to change it."
In an edit to the post, the woman clarified that by 'sickness' she was not referring to her husband having cold or broken bones, but rather a chronic illness.
"However, if it's chronic/severe and requires so much time and playing around (diets, restrictions, special conditions, etc) then no, I had enough of those in my life," she said.
The majority of the replies agreed with the husband, saying the woman was not ready to be a life partner to someone if she didn't want to stay around through the bad times.
Reddit has since removed the post to comply with community guidelines.