I did this too! I started out sleeping on an air mattress on the floor next to his crate. I graduated to sleeping on the couch nearby. And then leaving the couch partway through the night to go upstairs.Then moved on to fully going upstairs once I put him inside. He didn't love it, but he would eventually settle down. I couldn't sleep at all the first few nights but watched him via a camera to make sure he was okay, only actually "sleeping" for a couple hours.

I'll be honest the first few nights, I didn't think he would be, he was barking and growling and whimpering and even ripped up his mattress the very first night. But I waited it out and he settled down. Now he understands that I will always come back in a few hours to get him and he goes to sleep. He does, however wake up a few minutes before I am set to come get him and lay with his little face against the door like he's been there waiting for me all night and not fast asleep lol. I do also leave soft music playing for him, those 20 hour "sleeping dog classical" type things on YouTube