DS went through a brief period of resisting bedtime when he was about 2. He didn't get upset, just didn't want to lie down and go to sleep. We found consistency and no interaction was the key.

So, DH and I decided together (so it didn't matter who did bedtime, it was done very similarly each time) that we'd do the bedtime routine as normal, then we'd say something like, 'goodnight, it's bedtime now. If you talk or call out, we won't answer, we've had our cuddles, story, drink (etc) and now it's sleep time.' Then we'd tuck him in, kiss/cuddle, night music on and stand at the door (he was happy with that as that's what we'd always done. If you're normally in the room, I'd stay there). If he tried to get our attention, we'd ignore him (I'd close my eyes and semi turn my back), if he got upset we'd go in, but not pick him up, cuddle or talk to him. This was rare though. Just sit or stand there, maybe put our hand on him or in the cot, but we didn't make eye contact.

If we talked to him (that's enough, sleep time now etc) then it was like we'd pressed his 'reset' button... But when we didn't interact, he'd get bored and go to sleep much more easily and quickly. The phased passed quite quickly if that helps to know

I also read that if it was taking an hour to get them to bed, to temporarily make the time they were falling asleep their bedtime. Bring it forward by ten mins every few days til it's back where you want it.

Oh, and I agree that DH should do it for a few days to give you a break