if i share a joint phone account with my spouse and need to get her text messages printed out is that possible without filing for divorce

I don't think this is a legal question as much as a question you need to ask your phone company.  If it is possible for you to access the account to print out the text messages, then I think you can do it.  It largely depends on whether you are privy to her password and if you are, whether she knows that you have it.  If she knows you can access her account then she has no reasonable expectation of privacy.  If however, you do not have access to her account, then you need to ask yourself why you feel compelled to view your wife's text messages and why she would want to hide them from you.  If you are not contemplating a divorce, it sounds like marriage counseling is in order.