HELP - Baby won't sleep without boob

Are there any other ladies whose bub won't sleep without the boob? My son won't settle himself without the boob during the night. I'm waking anywhere from every 30mins to 2 hours all night with him looking for the boob. He's not hungry because as soon as it's in his mouth he goes straight back to sleep. I can't get him in his own bed because he wakes too often for me to keep getting up (i have tried though). Does anyone have any tips on how i can get him to stop doing this? He hates a dummy and i put him in a sleeping bag at night (he hates being swaddled). This constant waking and needing the boob has been going on for approx 6 weeks now and I'm losing my sanity!! He's 4 months and i know there is a sleep regression but this started when he was about 2.5 months