Respect for the Mother at the Expense of the Wife

My husband's mother is ill. My husband has only one brother who lives in a distant city. My husband takes responsibility for his mother. He doesn't care about my opinion and stays with her on Shabbat and holidays, leaving me alone. It's especially hard for me emotionally, as everything seems obvious to him, and everything is for his mother at my expense. He doesn't even consult or inform me in advance. What should I do? Should I give in?

Shalom and blessings 

First of all, blessed are you for engaging in the important mitzvah of honoring one's mother, may you merit the Torah's blessing for long life and well-being. 

It is forbidden for a person to commit any sin in order to honor their parents. Therefore, it is certainly a mistake to honor the mother while causing distress to the wife. 

On the other hand, since your husband is obligated to honor his mother, it is necessary to find a way to respect her on one hand and to ensure peace in the home and provide for the wife's needs on the other. As I understand from the question, this is definitely possible. 

I feel that what is needed here is simply communication between you. Explain what bothers you about his behavior and understand how you can meet the mother's needs without harming you. For example, talk to you before he volunteers to go to his mother, take you with him on Shabbat to her, and so on. 

If you see that he does not understand your problem, demand to go to a counselor or agreed-upon rabbi to teach him the rules of respect for a married man.