mommas I need your opinion !!

I will soon be a single mom due date April 30th! The one thing I can’t figure out is what last name to pick ... do I use mine or my ex’s . At first my ex wanted to be involved and then out of nowhere he now is telling me to stop messaging him and seems like he doesn’t want to be apart of his child’s life when that times comes... my mom is on me about giving my son my last name so we can match but I don’t want to take that away from my ex’s family as I am very close with his family just no longer him and with having a son the last name carries over , I don’t want my son to grow up and wonder why he doesn’t match his dad or he doesn’t match me .. my question is what would you do ? A lot of people have told me to use both but I just don’t like the look or sound of it .