@kidbuu699Vulgus has several stories that may qualify, but the author's stories usually start with a male domination situation that later develops into love.
https://storiesonline.net/a/Vulgus
Note that I haven't read all of these, but stories that you might want to check out include:
Be Careful What You Wish For - The new neighbours meet a 14-year-old girl and her mother who both want to be dominated.
The Bitch Next Door 1 & 2 - A widower takes in the woman next door and her kids, girl:15 and boy:13, on the promise that the woman will be his sex slave. The kids soon get involved too.
It Was This or Go To Prison - Guy catches a single mom and her 16yo daughter robbing his house and offers them an alternative to prison.
The Loan Shark in Our Life - A happily married mother of two teens takes out a loan with an unusual payment plan.
There are also several others that have similar family combinations, but without the romance outcome, like Three Stars Are Born in which a woman who has been making porn is offered a raise if her three kids join her. No one is happy about it, but the family needs the money.
Be aware that these stories are old enough that some violate the no-under-14s rule. Also, in addition to the Male-Dom, many Vulgus stories include reluctance and rape, BDSM and rough sex, gang bangs, and forced prostitution. Some also include water sports, bestiality, torture, and other extreme content.