A man or woman who sincerely fears for his safety or the safety of his children can certainly live apart from his spouse without waiting for counsel from clergy. The preservation of human life takes priority.
The Church, "the pillar and foundation of truth," has the power to "bind and loose," i.e., indisputable ecclesial authority, and has the authority to lay out the principles for a valid separation.
But the Church does not grant divorces and encourages couples to do whatever is reasonably possible to repair their marriages.
Far as I know, the Bible says only adultery is "legitimate". The catholic "church" says otherwise.
According to Catholic Answers, the meaning of the term, "pornea" is debated among Scripture scholars. Regardless,
Jesus’ and Paul’s constant and forceful teaching about the permanence of sacramental marriage as recorded elsewhere in Scripture makes it clear that Jesus was not making an exception in the case of valid, sacramental marriages. The constant teaching of the Catholic Church attests to this as well.
The Catholic Collegeville Commentary states: “Jesus’ teaching on marriage and divorce in Matthew 19, verses 4–9 first cites Gen 1:27 (v. 4) and Gen 2:24 (v. 5) to the effect that in God’s original plan of creation marriage was indissoluble and no human agent could end such a union (v. 6). In the Old Testament (see Deut 24:1–4) divorce was allowed only as a concession to human weakness. This was not God’s original intention (vv. 7–8). Once again Jesus assumes the role of the authoritative interpreter of the law, and in verse 9 he forbids divorce and remarriage absolutely, except for the case of porneia — most likely a marriage contracted within the degrees of kinship forbidden by Lev 18:6–18 (see the commentary on Matt 5:32 below). There is little doubt that Jesus regarded marriage as indissoluble (see Mark 10:11–12; Luke 16:18; 1 Cor 7:10–11)” (Bergant, D., & Karris, R. J. (1989). The Collegeville Bible Commentary: Based on the New American Bible with revised New Testament. Collegeville, Minn.: Liturgical Press).
“The antithesis concerning divorce seems to repeal or reject the permission and procedure found in Deut 24:1. According to Jesus, divorce is not allowed (see Luke 16:18; 1 Cor 7:10–11; Mark 10:2–12; Matt 19:3–12). The Matthean versions of Jesus’ teachings on divorce include some kind of exception: “unless the marriage is unlawful” (5:32; 19:9). The Greek word is porneia, which refers to some sort of sexual misconduct or irregularity. In Acts 15:20, 29 porneia has to do with marriages contracted within the degrees of kinship forbidden by Lev 18:6–18, and thus technically incestuous unions” (Bergant, D., & Karris, R. J. (1989). The Collegeville Bible Commentary: Based on the New American Bible with revised New Testament. Collegeville, Minn.: Liturgical Press).