We co slept with our ds and he still comes in early in the morning for some snuggle time. If he is still in a cot maybe look at putting him in a single bed. You could even put a mattress on the floor of your room for a while and slowly move it out. Make a big deal about having his own room but don't force him into being there. With the new bub he is probably just wanting to make sure he is still a special part of your life. If you can maybe drag a mattress into his room and camp in there for a few days ( I've been doing this for two days as DS is very sick with a cold ) Hope he settles in soon for you.