K.B.
I would check with your doctor. I have a friend who was told to only pick up her youngest child in an emergency (I believe the doctor used a runaway train barreling toward him as his example.) She had a miscarriage previously and had difficult pregnancies so they were very careful with her throughout her pregnancy. She taught him to pull himself up into the car and into his carseat on his own. He took naps on the floor so she didn't have to lift him into his crib during the day and her husband put him in the crib at night. It wasn't easy, and I have no doubt that she had a few occasions when she did lift him out of necessity.
If you do need to stop lifting him think about it this way. Once the baby comes you won't be able to hold him and the baby at the same time anyway. If you teach him now to do more things on his own and not be lifted often it won't be as surprising to him once the baby is born. Hopefully he won't associate not being held with the baby's arrival and you'll cut down on a little bit of the jealousy.
Good Luck,
K.