You can tell your partner some things that will help the relationship. You need to evaluate your partner and decide what would be wise to tell them and what would not be wise to tell them. She says it is because she has recently had a baby. It has been eight months since my daughter was born. That is fairly normal.
Women biologically have a different basis for their sex drive.
Both partners need to accept that. You need to schedule sex and make it a priority. You need to have sex regardless of how you feel. Try to make sex good and continue doing it regardless of what's happening in your life. You shouldn't say you don't feel like having sex because you just had a child.