If a wife is suffering unjustly from a neglectful or abusive husband should she see this as an opportunity to share in Christ's sufferings instead of as a reason to opt out of the marriage?
Reply: She MAY treat this as an opportunity to share in Christ's sufferings, just as someone who is being victimised at work by religious or sexual discrimination can decide to simply suffer it. Or a child who is bullied at school or a man who is mugged or a woman who is raped can decide to say nothing and bring no charges against their persecutors. This is their right, but it is not their obligation.
Jesus DID encourage people to forgive those who broke their marriage vows, and forgive and forgive again. He said they should only divorce "for hardness of heart" - a reference to Jer.4.4 which is the only place where this word occurs in the context of divorce & remarriage, as I point out in my books. Jeremiah is talking about God's divorce from Israel, which he delayed and delayed, forgiving Israel again and again, till God divorced her when it was absolutely clear that she was not going to repent.
Jesus commands us to forgive someone 70x7 times IF they repent (Luke 17.4 - though Matt.18.21f omits "if they repent", probably because it is too obvious). We can also forgive them and give them another chance if they don't repent, but that is an option, not a command. And we cannot repeat that kind of forgiveness endlessly - just like God decided finally that it was counterproductive to continue giving Israel more chances.