Aquarius walked out on me and my baby why?

i was already pregnant when we started dating he told me he didn't care that i was pregnant and he love me and how he wished the baby was his he rubbed my stomach every time he saw me and brought me paternity clothes. once i had the baby he start ignoring my phone calls once i start crying telling him how he hurt me and how much i love him he start treating me good again and told me he love me. now he want us to move in together. why did he do a 360 on me