Hi Dads, advice please! long

Hindsight2020

Hope you don't mind me posting here, this is kind of a vent AND asking for advice...

SO & I are parents of a 23 month old son and a 3 month old daughter.  DS was not "planned", but SO wanted a child and (apparently) luckily got a boy.  Once I got pregnant, I knew I didn't want an only child, so I thought about when we could have another.  SO, however, wasn't sold on having another.  But he didn't take any precautions to prevent another child, even though he knew I wanted another one. So we got pg again.  I honestly worried about how it would be with not only 2u2, but once we learned she was a SHE, how SO would do.  Long story short, he ISN'T DOING WELL. And I think its's because she's a girl. 

She's not an easy baby...has reflux, cries a lot, and I'm apparently the only one who can soothe her.  Or so SO says....he doesn't even TRY; as soon as she starts fussing, he dumps her in the bouncy seat and says she's a "tit baby" (she's FF, BTW).  I try to make him feed her, but she does start crying when he takes her...he NEVER tried to bond with her and I think it's b/c she's a girl...when we fought earlier to the point of me kicking him out, he actually said "Can I have DS?"  As though he can just choose to parent one child and not the other...I'm at my wits end here...  He never kisses or talks softly to her, when he DOES dare to hold her...I feel like he just "tolerates" her...and she deserves MUCH more than that from her FATHER...

Do you have any advice on how to get him to MAN UP and parent his daughter?  Or should I just cut my losses and be a single mother of 2 kids...(because there is NO WAY IN HELL he's "getting" DS as he wanted)

THANK YOU!!!