My fiance and I can't figure out what to do about his nephews. We are having a small outdoor wedding. My niece is our flower girl. We have friends with kids, all under the age of 4. We love all of these kids, including the nephews, but the nephews are extremely poorly behaved, to the point where it's not cute at all. We want to invite the other kids, but we don't really want to invite the nephews. I've been at weddings where kids misbehave and I never think it's a big deal. However, I've never seen these kids sit still for a meal (they're 6 and 3) and I have seen them scream at their parents (their father screams back, doors are slammed, etc.). They have good moments, but not nearly as often as the bad moments.
We are heartbroken over this decision. We know this may cause a huge rift in my fiance's family. We know the kids will be hurt (that makes me most upset). I'm looking for any advice - how to include them and help assure they'll be good, how not to include them and it be ok (I know this is unrealistic).
Thank you in advance for your insight!