Boys, this is what we did.
Firstly we moved him into his own room (as we were waking each other up), got blackout blinds for his room and a dream sheep.
In the evening I would follow his routine: song, bath and feed and then take him upstairs to bed at 6.45. He usually fell asleep during the feed so I would just gently wake him by burping him so he was sleepy but awake. I then put him in his cot, put his sleeping bag on, gave him a comfort muslin, said goodnight, stroked him, switched on the dream sheep and left the room.
The first night he screamed as I left the room so I stayed outside the room for 2 minutes (with timer as it went so slowly), went back in and did the same: said goodnight, replaced muslin in hand, stroked him and left room. I didn't stay in the room for longer than 30 seconds. I then stayed outside for 4 minutes and did the same. His crying became punctuated with stops and yawns and he'd fallen asleep between 4-6 minutes. Idea is to increase by 2 minutes each time but he fell asleep before I got to 6 mins. I did this for about 3 days and by 4th he was not crying and (I was looking on video monitor), rolling around a little before going to sleep.
I wake him for a dreamfeed at 10.45pm and then usually don't feed him again until 7am. Now my Dh is able to comfort him if he wakes in the night (before the only thing he wanted was a feed) by saying goodnight, stroking him, giving him muslin and turning on the dream sheep. I think the white noise and the muslin have replaced a breastfeed as a sleep cue as he will quickly go back to sleep with the dreamsheep on.
Hope that helps. Don't feel guilty, remember it is far better for him to learn to self settle and have quality sleep as well as a mum who has energy!