I understand so well how you feel. I slept with my son on my chest for the first 5 months of his life. He is 2 1/2 now. Everything you described fit my own situation to a T, and it was just not sustainable for me. I embarked on a lengthly process with the goal of having him sleep beside me, and at times to be able to sleep without me by his side, particularly for naps. The way I did this was to basically move him off of me and then away from me bit by bit, body part by body part. I learned how to nurse him on my side and that became a lifesavour and still is to this day. I hated nursing lying down at first and it took me months to get the hang of it. I would recommend you persist a bit more to see if you can eventually find some comfort with doing it that way. He still sleeps with us and still wakes frequently throughout the night and I nurse him back to sleep, but we're miles ahead of where we were at 6 months.
I started by just having him snuggled in beside me, always touching me, but not on my chest. He resisted this at first and it took a number of nights until he was ok with sleeping right beside be. Then as he became comfortable with this I started to move my legs away from him, sleeping with just my upper body and arms touching him. Once this was accomplished I began to remove my outer arm from his body. Next I just rolled my body away from him a very small amount. The next step was removing my arm from being curled up around his head. And so it goes.....It worked for me and my son and we got to the point that I could nap/night time sleep beside him and nurse him back to sleep as needed. For naps each day I would try to be just a bit farther away from him on the bed, then eventually to on the floor, then at the door, then outside the room.....We got to the point where I could put him down and when he was fully asleep I could leave the room.
It was a long process but it was the only thing that I felt would work as I could only handle small progressions that didn't cause any crying. Now at 2 1/2 I still lay with my son until he is fully asleep but I can leave the room and we have a video monitor so if he wakes up I go in and comfort/nurse him back to sleep and then I go to bed when I'm ready. The video monitor was key to helping me get through it all. It gave me the peace of mind to leave him on our bed while sleeping and know that I could zip into the bedroom if he was moving toward the edge. It was easiest to keep him in our bed as that was the sleeping environment he was used to. I recommend a video monitor!
Good luck and I hope you are able to find something that will work for both of you!