Answer: Your question captures the dilemma so many women who are in an emotionally abusive/destructive marriage experience once they prioritize their sanity and safety over keeping the marriage together. They fear God's anger and his disappointment. They fear being a poor representative of Christ and feel guilty when they finally say "I can't do this anymore."
I deeply appreciate that you don't take your marriage vows lightly. We ought to press pause for self-examination, prayer and Biblical counsel if ever we consider separating from our spouse, so that if we separate, we are separating for biblical reasons and have as clear a conscious as possible.
Let me encourage you that God values physical safety and relational safety as much if not more than you do. For example, in spite of God's general instructions to submit to the laws of the land and to higher authorities, when David feared for his life because of King Saul's jealous rages, God didn't instruct David to "submit to the King and trust me to take care of you" Instead, David fled, always respecting the position of King Saul, but not allowing himself to be abused by him. (Read 1Samuel 18-31 for the story.)
In another example, when Jesus was born and King Herod sought to exterminate all the Jewish babies two years and younger, God told Joseph in a dream to flee to Egypt until it was safe to return (Matthew 2:13-15).
When Rehab hid the Jewish spies, she lied to keep them safe, and God commended her (Hebrews 11:31). I suspect those who lied to keep Jews safe from the Nazi army were equally commended by God.
Jesus himself valued safety and said that even the well-being of an ox was a higher value to God than legalistically keeping the Sabbath by not working (Luke 14:5).
Safety is an important component of trust, especially in marriage. There can be no freedom or honest communication if someone feels afraid or is threatened either physically and/or emotionally or has a price to pay whenever they honestly share their thoughts and feelings.
Women (and sometimes men) fear taking measures to protect themselves because they've been taught it's unbiblical or ungodly. They suffer endlessly with verbal battering, even physical abuse, believing that by doing so they're being godly martyrs. Keeping the family together at all costs is seen as God's highest value.
Yet Proverbs 27:12 teaches us, "The prudent see danger and take refuge."
Sanity is also an important value to God. By sanity I don't just mean good mental health from a secular point of view, but good mental health from God's point of view. Again the writer of Proverbs warns us of the devastating consequences of living with a contentious and argumentative person (Proverbs 15:4; 17:1; 25:24; 26:28).
The scriptures are clear. People influence and impact us both for good and for evil. When we live with an abusive, destructive, manipulative and/or deceitful person, it definitely takes its toll on our mental, spiritual, emotional, physical and spiritual health.
Being sane from God's perspective involves knowing, believing, and walking in the truth. Jesus says, "If your eye is good, your whole body is filled with light. But when your eye is bad, your whole body is filled with darkness. And if the light you think you have is actually darkness, how deep that darkness is (Matthew 6:33). The apostle Paul says by nature we exchange the truth of God for a lie and that the more we do that, we become more and more insane (depraved mind) (Romans 1:25-28).
Walking in the light and truth are important values of God. When you live with someone who prefers deceit and darkness and who twists and manipulates the truth, it can be very stressful.
However your question is "are you being a poor example of Christ to others by leaving?" My answer is maybe. You also could be a poor example of Christ by staying. You see, it's not whether you leave or stay that determines whether you are letting the love of Christ rule you, but how you leave or how you stay.
There are people who choose to stay in a destructive marriage (for lots of reasons) and are terrible examples of Christ. They are bitter, angry, spiteful, depressed, resentful and demonstrate no joy, peace or hope in their countenance. Likewise, those who leave a bad marriage can also leave with those same negative emotions in control rather than Christ.
So, what would it look like to be Christ-like and God-honoring even while leaving a destructive marriage?
Here are a few thoughts for you to ponder. The apostle Paul says that we're not to only look out for our own interests but also to look out for the interests of others (Philippians 2:4). You are looking out for your interests for safety and sanity by leaving. That's not ungodly or sinful. But if you want to be a godly wife, you must also look out for your husband's interests. So what is your husband's greatest need right now? Is it to stay with him, make his dinner, be his companion and meet his sexual needs, or is it something far more crucial to his long-term well-being? I believe your husband's greatest need right now is to wake up from his slumber, from his darkness, and to come to Christ and repent of his destructive behaviors. The question you must answer is "would you more likely help meet his greatest need by leaving or by staying?"
Secondly, God calls you to love your husband, even if he feels like your enemy right now. That is being Christ-like. However, you must also understand that unconditional love doesn't entitle someone to unconditional relationship even with Jesus. The scriptures tell us that our sin separates us from close relationship from God. It doesn't separate us from his love, as Paul tells us that nothing can separate us from God's love (Romans 8:38,39), but it does separate us from his Presence.
If Jesus doesn't offer unconditional relationship with everyone even when he loves them, I don't think he expects that of us either. Sin not only separates us from God, it separates us from one another. Until your husband can see his sinful heart and actions as damaging not only you but your marriage and is willing to actually do the work it takes to change them, it may be most Christ-like to stay compassionate toward him yet separate from him.
There's one more thing. For your own peace of mind, please ask God to show you how to represent him well in this time. You must let go of your desire for everyone to agree with your decision to separate. You may be Christ-like in all your actions and attitudes, and people still may not like it. Jesus represented the character of God perfectly, and yet there were those, especially religious leaders, who did not approve.