How would you feel if the law didn't recognize incompatibility of spouses as grounds for divorce?

I get the impression that if a child comes to the attention of child protective services (henceforth "CPS") and CPS either refuses to investigate or conducts an investigation but concludes that no crime was committed, then the child is placed back under the custody of the person who had custody, and who may have been abusing the child.

Exactly what is abuse from a legal point of view? Obviously it is easier for two biological parents to abuse their child than it is for one adult to abuse his or her adult spouse, because children are generally more vulnerable than adults and because two can often overpower one. Also, neglect can easily occur if the right hand (one spouse) doesn't know what the left hand (the other spouse) is doing with respect to a given child.

Under the law, children are entitled to room and board, but they can get that from any number of households where there is already at least one child who is legally under the custody of the people who run the household. If a child were to leave the custody of his or her biological parents and leave a vacant room behind, then the biological parents can offer room and board to others and use the money to pay for support of their biological child. If it turns out that nobody, child or adult, will tolerate the conditions for long, then the room and board has no market value and the biological parents might require some government assistance to help pay for room and board for their child.

It seems odd to me that the legal entitlement of room and board is transformed into a pretext for giving adults an opportunity for concealed interactions with young people who might very much wish to avoid the interactions altogether or might wish to at least have all of the interactions occur in public where there are third-party eyewitnesses.