As-salam you alykum

I am a female and have been with the same man for 8 years and we have lived together for 4 years we have two children. We turned to islam about two years ago. I have been asking him if he is going to marry me and he says yes, but has not made any steps to getting the nikah performed. It is now close to ramadan and I am excited to fast as before I have been pregnant or breast feeding. I would like to know if my fast will be valid as I will still live with this man as niether of us has anywhere else to go.