Joint legal custody (joint decision making) is very much the norm and may very well be granted. Joint physical custody is also very normal, however that is not really what he is asking for. A 50/50 timeshare is apparently what he is asking for. He is also assuming that a 50/50 timeshare means no child support. That is not necessarily the case. A 50/50 times is NOT the norm and its very unlikely that he will get that with your set of facts.
However, what WILL happen is that he will end up with a parenting schedule that will be court ordered and that you will be required to honor.

