Opinions please

Stormy • Hi! I'm 20 years old have a 1 year old son and just gave birth to my daughter April 4th
So my friend has wanted my husband to let her use his sperm to get pregnant being as shes in a lesbian relationship and they want a baby after they get married.I just dont know how to feel he is willing but Im hesitant being as Im his wife and feel like I should be the only one having his babys but I also want to help my friend...How do I become ok with this?