You are in a situation.

Regarding pregnancy turning her into everything you don't want to be with, pregnancy is a profound situation biologically and effects nearly everything. Its not a permanent situation.

Regarding some other things you've said it sounds almost like you want to act in a way that is callous and self indulgent without any one else forming the opinion that you are callous and self indulgent. You need to do what you need to do. Other people's opinions don't really matter. What is your own opinion about your desires and plans? That is what matters.