Why do you want to change his habits now? You're not going to work for 3 more months. If you like sleeping together, then enjoy it for a little bit longer, if you like.
You just need to weigh up whether you like the weight of his warm sleepy body more than you like sleep. (this is possible!)
When you REALLY want things to change, you will find the strength to do CC or whatever.
If you're already at that point, then something I've learnt the hard way, is that you need to make changes REALLY gradually. Don't suddenly bung your LO into own cot, refuse to feed back to sleep and expect him to go through the night.
Start by moving him into his own cot, and BF settle him every time he wakes. You may find you sleep more deeply between feeds when you're not worrying about rolling over onto him. I do.
Then start enrolling dh into the "every second wake-up" rule or whatever you decide to do next.
The other thing to say is, if you ARE going to do CC, the younger you do it, in a way, the better. It's really hard to listen to your LO crying for half an hour. But when they're screaming "Mummy! Mummy! Mummy! Mummy!" it's even worse!
I'm facing weaning DS1 (2.7) off the dummy in the near future. It's going to be hell!
Also, the other thing is sometimes my baby (DS2 5 months) just wants me to go away so he can get on with sleeping. If I stand over him, he thinks I'm going to pick him up. So I just have to leave him to cry occasionally. It's okay. He's not going to die. And if he gets really hysterical, I go and give him a cuddle.
(This is all day naps. He's a hopeless overnight sleeper but still very very small so that's okay)