Like your partner has said, do what makes YOU happy! It is your life, not theirs! If they dont approve then it is their stress not yours! I know how you feel though, i dont like anyone being upset with me, but at the end of the day will you be happy with them making the choices for you?
Are you able to do both at all.. like do Uni part time? One day or evening a week or something? Then if you have a second bubs you can express and your partner can feed of an evening while youre at uni that night? I know its a big decision to make, but that decision is soley yours and your partners, dont let anyone else pursuade you on the choices of YOUR life.

Best of luck