All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, is His slave and Messenger.
As a wife, you are entitled to live in a separate accommodation, which is an obligation on your husband as per the Sharee‘ah. This obligation is further emphasized by the promise he gave you. Therefore, it is incumbent on him to provide a separate accommodation for you to the best of his ability, and you are not obligated to live with any of his family members and relatives, nor is it incumbent on you Islamically to serve his family or take care of his mother, unless you willingly choose to do so.
You also have the right over him that he maintains justice between you and his other wife, whether you are both living with him in the same country or in two different countries. It is impermissible for him to spend longer periods of time with his first wife without your consent. Ibn Qudaamah said in Al-Mughni: “If a husband has two wives in two different countries, it is obligatory on him to maintain justice between them (in terms of overnight stay), since he has chosen to make their accommodations distant from each other, and this (separation) does not waive their rights over him in this regard. He is obliged either to travel to the distant wife when it is her turn or to bring her to the country where he is staying with the other wife. If she refuses to come although she is able to do so, then her right is waived due to her Nushooz (i.e. being a disobedient wife). However, if he wants to maintain justice between them with regard to overnight stay while each of them lives in her respective country of residence and it is not possible to stay with each wife every other night, then he may spend a specific period of time with each of them according to his ability. For instance, he may stay one month with one wife and one month with the other or more or less according to his ability and according to the distance between the two countries.” [End of quote]
His plan to bring you to stay with him for a month or that he travels to stay with you for a month and stay with his first wife for the rest of the year is unfair unless you willingly give up some of your right in this regard.
Our advice to you is to try to reach an understanding with your husband in light of what we mentioned and that you work together on pursuing all the means that would preserve your marriage.
Allah Knows best.