5yo sibling jealousy

[Justnoidea]

My DC1 is 5 and DC2 is 3. DC1 is really jealous of me (much less so DH) giving any attention to DC2 and it’s really getting us all down, especially over the holidays as we’ve all been at home together.

I do give each of them 1-1 attention but when it is DC2’s turn, DC1 will try to intervene/disrupt as much as possible, low level at first but will ramp up to eg trashing the duplo tower we have just built, or physically pushing me. We use warnings, then time outs/removal of tv but nothing has worked so far. We seem to be stuck in the classic rut of DC1 preferring the negative attention of being told off over me spending 1-1 time with DC2.

It has been like this since DC2 was born though goes in phases. Fortunately this is all directed at me - DC1 is kind to DC2 and they actually play really well together often.

How can we break this cycle?

What is happening with DC1 when you're having the 1-1 attention with DC2? Is he with his dad, or has he been set up with an activity, or is watching something he enjoys? Or pootling around playing by himself? Since if it's the latter, I'd try to set conditions for success by ensuring DC1 has something else engrossing to be doing when you want that 1-1 time with his brother! If he's already a bit bored and left to his own devices he's more likely to seek out that negative attention; 5yo aren't the best at playing by themselves for any length of time. If on the other hand he's abandoning something really fun he should be enjoying with his other parent, to come over and be disruptive, then that's maybe a trickier level of jealousy.