husband and his blackmailing ways

I don't know how much longer I can take. my husband doesn't want another child however I so i am desparate. i have a child with my husband and he has a 13 yo daughter with a one night stand who we have monday to Friday and have done for 6 years  I feel like my family isnt complete. we are moving house and even he was like box room ideal for a nursery and now he is like you gotta do this for me to agree to have a child. I don't want a child i want holidays and to relax even our child was not what I wanted but his first was. our boy was planned we caught first time etc. I am broken. constantly go in circles.