Can one use their maaser money for Yom Tov expenses?
Can ones wife give her husband her maaser money if he is poor?
In general, maaser money cannot be used for mitzvos that one is obligated to perform, and since Yom Tov expenses are an obligation it can’t be used from maaser money. Regarding Yom Tov expenses, you don’t have to worry about them, because H-shem pays them back, so you won’t lose out. If the person is considered a poor then they don’t have to give maaser.
Regarding a wife giving her husband her maaser money earnings if he is poor, she may do so, as she is not obligated to give maaser, see sources.
May H-Shem help you with an abundance of parnossa and everything that you need.
Beis Din Shel Shlomo Y”D 1, B’orach Tzedakah 11-6, and 3-5. Regarding a wife giving maaser to her husband, if the money was earned while they were married then it technically belongs to the husband (as part of the kesubah agreement that her earning go to him and he has to pay for all of her expenses) therefore it is like giving him his own money, which can’t be called tzedakah. However since he is poor he doesn’t have to give maaser at all. Therefore she certainly can give her husband that money. It happens to be that even if a person is poor, there is still a benefit to separating maaser, and then using it yourself, see Orach Tzedakah 3-5.
If the wife’s money is from before their marriage, then the halacha may be different… let me know.