Sofa - seriously, I agree with another poster and you think I am being unreasonable.
Likewise I disagree with the comment it is like going to GParents. SDCS come to their home and life goes on with them here and we do do some fun things aswell, them on their own, joint etc etc. Think that is one of the worst ways to treat the SDCs - this is not weekend aprty time it is everyday life.
"To me it makes sense he would have to do more than me when they are here so get less downtime. He has 100% of the looking after 2 of his children and 50% of the looking after 1 of his children to be responsible for. He can ask me to help out (and I do eg. Homework) but he needs to be spending time with DC. Otherwise I worry about the effect on DC of being dropped every weekend."
OP has her family - her DC and DP and the SDCs are not part of that and yes he does need to do things with his youngest DC - but this is being portrayed as if the minute the SDCS enter the house he does not speak, look at o play with his youngest DC - which I seriously doubt.
OPs child is 2ish , DSCs are teens so maybe 5 more years and probably less of them coming over all the time. OP does not need to be so obsessed that on 4 days of the month - her DC is not the centre of attention - the child needs to learn that Dad has other children and they are equal aswell.
Some of the suggestions on here are bordering on ridiculous - the DF should now do bed time with his NRP teenage children. Seriously, I have 3 teen DSC - who take themselves to bed whenever, if you are lucky you might get a grunt ! Even the stroppiest teen ( middle DSC-def in that category) would not want Daddy putting her to bed at the age of 15!
OP is obsessed with equality in an unequal world - in her world, DF must play with DC 50% of the time her SDCs are here because anything less is wrong.