Personally, I think it's wrong to muddle the 2.
It's different because I'm not sexually or romantically involved with my male coworker, barber or church member. If someone's role in my life is as a fuckbuddy, that is a path that is fine to have but not one that crosses with family life.
And if you do that with one fwb, why not the fwb u have the following year? or the year after that?
where is the line drawn? that's subjective, but I believe in keeping this kinda shit separate.
A. Why do you think it's wrong?
B. You would put a complete stranger over your fuck-buddy, (meaning, you will introduce your child to a deacon/pastor/ if he ask lil bud buds his name, you won't be quick to shut it down eh?, but you wouldn't introduce your child to a fuckbuddy?
C. Fuck buddies varies, one could be a cool ass person, we like the same shows, like the same rap artist, comedians etc, one could be just on some, come over get this dick and be out, we don't talk, we don't share anything common, don't call me asking how my day going, we just str8 fucking, one could have kids themselves and just wanna know lil bud buds and that's it, not trying to build nothing with bud buds, just want lil bud buds to know who she is, so when he sees her in the house by any chance, lil bud buds won't be alarmed. I mean it's varies with your FWB situation.
D. You draw the line IMO if you know this will only last for x amount of time, you know how long you wanna fuck someone or have an idea (I think) when you start fucking that person. If you can see yourself as FWB with them for 2 - 3 years, you really think, that person sneaking in your house and leaving before lil bud buds wake up won't get tired for them?