Don't worry, you're not messing him up! Ours had a routine, but it was more around what we did, rather than the time it was done IYSIM? Ours was (and still is):
Dinner,
Changed for bed (gap between this and dinner if small child wired),
Brush teeth,
Story (or three),
Slowly up the stairs saying 'night-night hall, night-night landing' etc and then 'time for sleep' on putting down
Put down with soother in cot-bed.
If any proper waking after that then silently pick up, hug and gently rock for 30 seconds to one minute say 'night-night, time for sleep', very quietly and put back down again.
The pick-up and hug didn't always work, in which case we'd leave small child to complain for about 3 - 5 minutes before going back and repeating. That way, he's being re-assured there's someone there, but can't get second wind by being taken back out for play.
In terms of day-time naps - if small child was getting cranky then they'd be put down for 'five minutes quiet time' during the day (if they were still complaining after that point then we'd go in and say 'ok - enough quiet time' and take them up again. If they fell asleep, then great, they were tired.
I do avoid allowing napping to start past about 4 though as this did seem to affect the night sleep.
The above worked for us, but I'm sure you'll have a few other suggestions along shortly too. Go with your gut feel on what might suit your DS - you know him far better than anyone else does.
Also, can post what the rest of the day has in it for us if you'd like, but didn't want to add to the essay. 
By the way - you really, really are not failing him.