EAD is not a status, it is related to different status. So,

EAD can not affect any status. For you, once your spouse 485 with you, once you get receipt, if he or she is H1b, you will be H4. If the case is proved, both of you will be permanent resident. If the case is denied and he or she still keep H1b, you can still have H4. But, if he or she does not keep H1b, and he or she only use EAD to work, then your spouse and you is out of status. Here,it does not mean that EAD affect your status, but your spouse voluntarily give your h1b status.