Nah, usually the “wants to end the suffering” is referring to a suffering person dying or being killed, especially when an extremely sick person died in the event being described. Sometimes it’s used to reference just drugging yourself up beyond safe limits to remove chronic pain, generally also a very sick person. It’s pretty much never used to refer to killing someone else to free yourself from debilitating financial obligations. This isn’t an American thing, this is a poor word choice thing.

He is evil. He may have been suffering as well due to the evil system we live in and wouldn’t be in a humane system, but he could have just walked away or declared bankruptcy or divorced her or killed himself. All of those things are still harmful to her, but they’re better than being murdered. Whatever his hurts were, she didn’t deserve that. A bad circumstance doesn’t mean you can murder an innocent person you vowed to love and support and not be a bad person.