Pls help: My pd is reached this July.

Unfortunately my hu*****and has some problem getting his 出生公證. we are waiting for him to get it so that we can file together. However, we are worried that if we wait too long, PD may retrieve. I read through all the posts here and it seems that as long as we are married before I get my greencard, he can file 485. If this is true, I can file first and he can joion later when he has his 出生公證.Thank you so much.