1 Peter 3:7

7 You husbands in the same way, live with your wives in an understanding way, as with someone weaker, since she is a woman; and show her honor as a fellow heir of the grace of life, so that your prayers will not be hindered.

Husbands are to be submissive in the same way as the wives; but not to her as a leader over him (he is to be the leader). His submissiveness is to God in his duty of understanding that she is a woman who is not as strong (physically) as a man. Also, he must honor her as a fellow heir of God’s gift of life. And if he does this (if he understands her and honors her) his prayers will not be hindered. I take this to imply that if a man is not submissive in his duty to his wife he will be in disobedience to God, and thus God will reject all of his prayers. We can’t expect our prayers to be heard if we go against God’s will, especially in regard to our wives.