separating from husband with 7 month old

my husband and I are separating. it's been a long time coming and we are finally going through with it. we have a 7 month old son and 3 dogs and we own our house together, so there is a lot to figure out. i think for the most part we agree on what needs to happen, but my husband wants 50% custody and I just don't see how that will work. I'm in no way wanting to keep my son from him but I just can't imagine him being fully responsible for taking care of him for that long at a time. the most time he's ever had to take care of him on his own was about 4 hours. I breastfeed and my son only just started getting comfortable with a bottle, and he only just started sleeping in the nursery. I really don't want to end up battling it out in court, I just don't know what to do. I could really use some support and if there's anyone who has been through a similar situation any advice you have would be very welcome.