Yes. It's very hard to see reality when it's your own family. Or someone you know very well. Even if they have "issues." Unless they've shown a previous propensity I think for most it's super hard to imagine a loved family member could harm a child.
But if we set up rules for ourselves we can protect our kids:
Keep dating life separate from our families.
If you meet someone you really like, do a background check. It's about $50.00. Then, if they pass, date them for at least a year before you allow them to meet the kids.
Agree that no moving in, engagement or anything like that for at least another year or so. Really get to know them and their life and family and see how they interact. But don't let them babysit or be alone with your kids during this time.
For family, does brother, uncle, in-law, grandpa have a drug or alcohol issue? Violent behavior in their past? A criminal history that's more than infractions? Significant mental health issues? Socialization problems?
Don't leave your kids alone with them. Don't let them spend the night.
We can create logical checklists and follow them.