I need help ladies! *crying it out*

My 6 month old baby is super clingy and wants to constantly be in my arms. If I put him down to do something he usually crystal straight away. The only way I can get him to sleep is on the boob and if I try put him down into his cot he wakes straight away and won't go back to sleep. He's a terrible sleeper at night and will end up in my bed with me as it's the only way we get sleep. I've recently started trying the cry it out method during the day in his cot but he never gets close to going to sleep he just works himself into a state. I need some advice on this technique like how long do I leave him etc. My husband tells me I need to start leaving him till he falls asleep or I'm never going to get a break which I know on some level is true but there's no way I can just let him scream for that long. please mummas I desperately need some advice!