Child custody for infant

I’ve come to the hard decision that I need to leave my boyfriend.

Our son is 5 weeks old. He also has a 8 year old from a previous relationship. He has his 8 year old 50/50 custody.

Anyone have experience with child custody for a baby as young as ours? I’m breastfeeding so will the court give me sole custody for at least his first year?

I really want to exclusively breastfeed and pumping hasn’t been working for me. Would the court make him take formula just to split custody with my boyfriend?

I should add that my boyfriend is not abusive. He’s just extremely lazy and we disagree on time with family, religion, budget and how to raise our son. I don’t want to live my life miserable just because we had a kid together.

Please no judgements as postpartum is hard enough and I just want what’s best for my son and I.