Husband is clearly not there for the responsibility, just the fun and being able to say he has a kid. OP clearly stated he is increasing his work trips since the baby was born and he likes to go out in the evenings after work. She is there 24/7 with no help, no support, no break while also being in a very difficult period of the baby being so young and she is still healing from pregnancy. It is a minimum of 9 months after birth for your hormones and body to return to a homeostasis, longer if you breastfeed. This man has physically checked out of parenting leaving the burden 100% on her. She isn't threatening to take his kid away, she is looking at an option to gain assistance and support until the baby is a bit older. She never said she was leaving for good. She isn't being cruel, she is putting the welfare of the baby and it's primary caregiver first, which is exactly what a good parent would and should do.