Agoo it's tough, isn't it?
DS went through a faze of not wanting to sleep. In the end we had to be tough...but it was heartbreaking. We stuck to it though and now, by and large, DS sleeps right through.
What we did was to put him to bed asleep. This was a huge difference for us, as he'd always fallen asleep during cuddles and then transferred to bed.
This was not popular.
As he was in a toddler bed at the time (he'd just turned 1) he was able to stand at the top of the stairs and would cry down the stairs.
I'd go up, give him a cuddle and tell him it was time for sleep. Then put him back to bed.
Multiply this by about 30 times per night over the course of 4 nights, and you'll get the picture.
It was hard, and 1 night he saw it as a game.
It took a good few weeks to get through the standing at the top of the stairs, and he got into the habit of throwing his cuddly toys down the stairs to get our attention. We worked out he liked complete darkness and after a while when put to bed he'd stay there.
In the middle of the night we were a bit slack about putting him back to bed, and if we brought him into bed he'd think it was play time. So we had to learn to put him back to bed and tell him it was sleep time.
Touch wood, it now works.
Good luck, and honestly it will be better all round.