Need some advice and help please 😩

So I have a 3 year old boy and a baby girl on the way who is due April 26th now my son still sleeps in the bed with my and my fiancé and I wanna try and get him out of the habitat before his sister gets her cause she will be staying my room for a few months in basinet so I wanna get my son to start sleeping in his bed in his room but my son understands he has a sister on the way and I don’t wanna make him feel like just because I’m having another baby that I’m like trying to get rid of him or make him recent her or feel some type away especially being that he is really attached to me and we are very close!! So how should I go about doing this please help!! 😩😩🙏🏽