I don't have time to read all the other responses, so hopefully this isn't redundant.
Our state has a pretty reasonable schedule for gradually introducing more time with a NCP, when the parents split up while the kid is still an infant.
http://www.in.gov/judiciary/rules/parenting/index.html (You'll want to click on Section II-A.)
You should write up a proposal for your (ex?)-BF, showing that while you think the baby DOES need significantly more time with you NOW, you do plan to give him more time with her as she gets older
and this is what he can expect. You don't expect him to just be dependent on your whims, as time goes by. Then
do that and LET him threaten to take you to court! Most likely, an attorney will advise him that he can't get a better arrangement through the court than what you are offering and he'd be wasting his time and $.
In your heart, you know you must base your decisions on what is best for your baby, not on pressure, manipulation, fear or the path of least resistance.
And you know your baby needs to be mostly with you, right now. If HE were thinking about the BABY's needs - not his own - he would know you are right.
It IS true that the baby needs to bond with him, too. She just needs to do it in short, frequent segments, not three days away from you, four days away from him. If you've already agreed to that,
change your mind! You made the wrong call and standing behind what you promised is NOT more important than doing the right thing for your baby.
Although my state does not promote it as the standard arrangement, I DO think 50-50 custody (for OLDER children) is often the most fair. To an 8-year-old, Dad is not a less-important parent just because he's male. Dads can cook, supervise homework, drive kids to soccer, volunteer at school, tuck in. Dads who don't want to shouldn't have 50-50 custody, but those who do should have the chance - and kids should have that time with them.
But NOT 3 months after they emerged from their mother's body!!!!!!
Parenthood means self-sacrifice, especially when you make babies with someone you're not going to spend the rest of your life with. Later,
you will have to sacrifice time with your child, so your child can spend it with him. Now,
he needs to sacrifice the time he wants because your child needs to be with you.
Be strong. Do the right thing.