Since it seems that you are now only trying to get involved with your son, I would let your wife set the pace. I would also be grateful for every moment you get with him. It is probably the most difficult thing in the world to seperate a child from their mother. You need to start slow and build the trust with your wife. I would also suggest that when you do return him home that he is not hungry, and he is clean(clothes, face, and diaper).
I know you think you are entitled to time with your son, and you are, but I think it is in your best interest to slow down a little. Take the time you get with him and prove to her that you are a worthy father. Hopefully in time you will have the 50% that you would like.
Good luck
Me 37/W 32 S 5 D 4 ILYBNILWY 5/12 Sep 8/12 Starting to find myself 11/12 on