Just expect to give up a few evenings for this. Do not go back downstairs, stay upstairs on the landing.
Every time he gets out of bed you return him, the first time you tell him it is time for bed, 2nd time you say bed, 3rd time onwards no talking, no eye contact just return, return, return.
It is a battle of wills and yours has to be stronger than his.
Ds2 was a very poorly baby and slept upright on me in the day until he was over 1 year old. He was also put into his cot very sleepy. He had severe reflux, was under the paed at the hospital and the upright sleeping massively helped, plus his cot was propped.
When I made the decision that he would be put into his cot awake for his night time sleep, I laid him back down over 120 times that first night. I sang Tom Petty I won't back down in my head. The second night it I laid him back down about 40 times, the 3rd night, 3 times.
You have to realise that you have to commit to it, short term pain for long term gain. Every time you return him remember you are doing this because he needs to be in bed and you need to spend an evening with your husband.
You may wish to reward him if he stays in bed with a reward sticker chart or a small gift from the bed fairy 