I don´t know. I am dealing with the same stuff, my ds is 11 months now. Daddy has had both kids three days a week, a couple of hours all summer. Dd ( almost three years) is sleeping over tonight!!
My ex want´s them both to sleep over all weekend every other weekend. That is way too long and way too early for the baby. I have agreed to dd staying there one night each weekend. And I now think she is ready for that, she was very excited about sleeping over at daddys tonight.
As for the baby, he will continue as before a litlle longer. After that I think I will agree to overnights one night every weekend. The kids will then see their daddy to afternoons in the week and one overnight in the weekend. We are meeting with our lawyers on tuesday to talk it over. I hope this will be OK with him.
I don´t know if your ex will get him 50%, I dont live in the US. Here they can´t do that. Thank god!! I think overnights for a one-year old is too early, but I really don´t know what else I can do, if it goes to court he will get overnights anyway.
Best of luck to you!!