Ok, have come back tonight to add to what I wrote yesterday as it's bothering me that you're getting tonnes of advice, some of it very conflicting and this is likely to make you stressed.
The single most important thing you can do for yourself and your LO is RELAX. I know this is easier said than done when you're sleep deprived and worried but you really must try!! Note to self: remove bossy head now
I feel bad that I may have misled you in my earlier post because I forgot to mention a very important point. DS has slept for 10-12 hours a night every night since he was 8 weeks with a few exceptions, usually when ill or when he hasn't had enough milk/food during day to keep him going through the night. We put him down awake now as he's recently started becoming distressed after being put to bed asleep and as I mentioned, he's fine with this.
HOWEVER:
Up until about two months ago, he had NEVER gone to sleep (bedtime/naps/anytime) without a screaming fit of hysteria beforehand. He was a nightmare in this respect but we realised it was just his way and that he would go to sleep eventually and be fine. And we were chilled about it and rocked, cuddled, sung him off to sleep and now I even forget that he needed that because he certainly doesn't now (He's almost 8 months)!! So, things can and will change and I really do think that your attitude can help this along.
We'll all give you personal, anecdotal, firmly believed in advice but the best thing you and your DH can do is to sit down together, consider all the advice and options and make a plan that works for you.
If it doesn't work, change it.
Oh, and did I mention not to stress??