I told him it worked for the first hour and he said well it's not working now. I am so freaking annoyed he's not backing me up. He coulda tool him back but apparently didn't want to listen to him screaming. I see that point but seriously, he's going to to think that if I kick up a fuss I get to stay up and watch tv.
Oh that is no good, naughty DH!!

Firstly, on the late sleeping issue (I'll get to your naughty DH next!!) Does your DS still nap? Maybe my experience could help?

I have had similar issues with DD (although she was still in a cot when they began.) I would put her down at 7 (always have - and she used to go straight off to sleep) then all of a sudden she started to complain about it, cry and carry on and play and chat to herself until 10pm. I was keeping her in the cot in fear of what I would go through if she could get herself out of bed - exactly as you have described!

I discovered that her later nights were related to her day sleeps (based on the fact that we have always had a 7pm (ish) bedtime routine). I found that if she went for her nap after 12 I would undoubtedly have her up still at 10pm. Also it seemed she was ready to drop her naps in a small way but not entirely. So she may nap 2 days out of every 3.

Since I have been strict about earlier naps things have improved a lot here - and we have made the transition into a big bed without too much drama.

Now, your DH... you poor thing! There is no way you can sort this out if your DH lets your DS get up and watch TV with you

As you would know, at 2.5 he is well and truly cluey enough to know that if he pushes you far enough he will get his own way if he has in the past. You are obviously well aware of it but your DH has to understand that that move he made most likely set back your bedtime routine considerably!! (Although if you remain firm, he may figure out that Dad is the pushover and mum is not to be messed with - when you say something you mean it, so DH is setting himself up for more challenging behaviour later...)

Niadalla's suggestion of the baby gate on the door is a good idea, this is what I had planned if DD challenged us on the getting out of bed front.

If you can keep the rules consistent it should not take too long for a cluey little 2yo to figure it out, DD stopped getting up after 2 nights and 2 day naps. Although all children are different and some will push boundaries more than others so don't get too despondent if your DS takes a little longer.

I hope you can sort things out with DH to make sure you are both on the same page. After all the effort you went through to get DS to sleep calmly and sensitively, it would have been massively frustrating to have it all cancelled like that. Keep it up, it sounds as if you are doing the right thing, remain calm and consistent with him and he should work it out.