can u give a newborn baby your last name if youre still legally married to someone who is not the baby mohter

I'm sure it's possible, but I can't tell you that I'm sure it's wise.  You need to talk to a divorce and family lawyer about this;  one place to look for an attorney is our website, http://attorneypages.com

In some states, marital fault such as adultery makes a difference in divorce.  You might decide that you don't care, but it's always better to make this sort of choice after you get all of the information about what that could mean.  Without all the facts of your case, and not being a Louisiana attorney, I can't give you more specific advice.