Joint Custody (aka Shared Custody) – How easy is it to get?

Ex-Fiance' and I share a DD together (she will be 2.5 in May). He is filing with the Courts now an Order (essentially a Consent Order between us, as we negotiated it) for my having Sole Physical Custody and essentially him having Partial. We of course share Legal Custody and I'm fine with that. The other week [what I would only assume would be another lame attempt to stay in my life] he brought up the fact that "maybe, in the future" he would want to file for Joint Custody, implying she would split her time between us 50/50. Currently we live 32+ miles apart and he made a mention of his "thinking about moving closer" to me, as "there's no reason for us to be 50 miles apart." (We have it in our Consent Order that we may live up to 50 mi. apart max).

So, is this a right a he's just guaranteed because he's her father, or is it a more cut-and-dry process? If anyone need more info. to give an opinion let me know; I don't want to bog everyone down in potentially useless info. if it's not necessary. I'm just curious of other people's experience with this and how common it is, 1) to be awarded Joint Custody and 2) Reversing a Consent Order giving me Primary Physical Custody and then trying to change that and her/our style of living "x" amount of years later.

Thanks to all who read and respond!