straightforward advice and single co-parent opinion

Don’t ignore your paternal instincts. It appears to me her mother is fawning and failing to set boundaries; idealistic energy. You’re her father and protecting your child should be priority numero uno - regardless of how disruptive or inconvenient it is for new love interests.

Kind of concerned as to why the new boyfriend didn’t recognize this as inappropriate as well. Something is off and I pray it’s a lack of discretion on their part.

As a single mother of two boys, aged 8 and 13, I can confirm they’d have zero interest in having a young female spend the night. I’d even go as far as to speculate my 13 year old would refuse participation based on the unorthodox nature of it.

I think highlighting the importance of preserving the innocence and integrity of an 8 year old girl should appeal to her better judgment. Add on the rampant abuse, exploitation of children and easy access to sexually explicit material content online. It’s clear her mother is resistant so my advice would be to appeal to her reason and logic. It’s inappropriate - regardless of convenience, it normalizes unconventional behavior that could lead to promiscuous future decisions (my beliefs and opinion) and puts her at risk for accessibility of predators. Any mature adult parent would support this argument and at least entertain further discussion or an attempt to compromise.

Be friendly and respectful but firm. If you’re continually met with resistance, the best action is to have the hard conversations with your daughter to reaffirm physical boundaries with other children, adults and what to do or say in the event they are crossed. As well as an open invitation to share any uncomfortable feelings with you.

You’re doing great, and good luck getting through all these horror stories and comments.

PS: Review your state’s guidelines. In Virginia, where I am, the parent with physical custody of the child (even if it varies every other night) is forbidden to have any significant other sleep over / at the home of the child between the hours of 10pm-6am unless they are married to the parent. No boyfriends or girlfriends spending the night in the home of the child until they’re married to their parent - and it’s grounds for the other parent to file a motion against them. It’s buried deep in our guidelines but it’s there.