This page covers "Covenant Marriage in Arizona" http://www.supremecourt.az.gov/dr/Text/Covenant.htm

According to the page, here are the reason a person can obtain a legal separation.

The reasons for obtaining a legal separation differ somewhat, but also are limited. The court must have proof that any one of the following are true (these are listed in Section 25-904 of the Arizona Revised Statutes):

1. The spouse against whom the legal separation case is filed (the "Respondent") has committed adultery.
2. The spouse against whom the legal separation case is filed (the "Respondent") has committed a serious crime ("felony") and has been sentenced to death or imprisonment.
3. For at least one year before the separation case is filed, the spouse against whom the legal separation case is filed (the "Respondent") has been absent from ("abandoned") the home where the married couple resided and refuses to return. The law allows an exception. A person may file for a legal separation by claiming that the other spouse has left the home and is expected to stay away for the one-year period. If the spouse has not been away for one year when the court papers are filed, the legal separation case will not be dismissed by the court. Instead the case will be put on hold until the one-year requirement is met. During the one-year period, the court still may grant and enforce temporary orders for things like child support, parenting time (formerly known as "visitation") and spousal support (sometimes called "alimony" or "spousal maintenance").
4. The spouse against whom the legal separation case is filed (the "Respondent") either has (1) physically or sexually abused the other spouse, a child or a relative of either spouse who lives permanently in the married couple’s home, or (2) committed domestic violence (defined in Section 13-3601 of the Arizona Revised Statutes) or emotional abuse.
5. The spouses have been living separate and apart without getting back together for at least two straight years before the request for a legal separation is made to the court. The law allows an exception. A person may file for a legal separation by claiming it is expected the spouses will be separated for the two-year period. If the spouses have not been separated for two years when the court papers are filed, the legal separation case will not be dismissed by the court. Instead the case will be put on hold until the two-year requirement is met. During the two-year period, the court still may grant and enforce temporary orders for things like child support, parenting time (formerly known as "visitation") and spousal support (sometimes called "alimony" or "spousal maintenance").
6. Regular abuse of alcohol or ill treatment of a spouse by the spouse against whom the legal separation case is filed (the "Respondent") makes living together intolerable.
7. The spouse against whom the legal separation case is filed (the "Respondent") has regularly abused drugs or alcohol.