Wife's Prayers When Visiting Husband Living in Another State
Question

                If a husband and wife are living in different states because of their work and study situation, and the wife visits her husband for a few days from time to time, does she have to put the prayers together and shorten them, as in the case of the traveller, or is her husband’s house regarded as her house?
Praise be to Allah.
      If her usual place of residence is in her state, and she is 
      only visiting her husband for a few days, then her husband’s house is not 
      regarded as her home; rather it is like any other place to which she may 
      travel, if the distance between the two states is the distance at which 
      shortening prayers becomes permissible, which is approximately 80 km. So 
      she should shorten her prayers during this trip, but if she has decided to 
      stay with her husband for more than four days, she should offer the 
      prayers in full from the time she enters his state, because in that case 
      she comes under the same ruling as one who is a resident. But if she 
      intends to stay for four days or less, then she should shorten her 
      prayers. 

    When it is permissible to shorten the prayers it is also 
    permissible to put prayers together. It is also permissible to put prayers 
    together for other reasons, such as illness or difficulty (in offering each 
    prayer at its time). 

    But there is a difference between shortening prayers and 
    putting prayers together. Shortening prayers is a confirmed Sunnah (Sunnah 
    mu’akkadah) for travellers that should not be neglected. As for putting 
    prayers together, it is permissible, so the traveller may put prayers 
    together or he may offer each prayer at its particular time. 

    Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) was 
    asked: I live in al-Qaseem, but sometimes I go to Riyadh to visit my family; 
    I have a room there and I stay with them for two or three days. Can I 
    shorten my prayers if I pray on my own? Do I come under the ruling on 
    travellers? 

    He replied: Yes, you come under the ruling on travellers, 
    because your place of residence is al-Qaseem, and when you visit your family 
    it is the visit of a traveller. Hence the Prophet (blessings and peace of 
    Allah be upon him) shortened his prayer in Makkah, although he had 
    previously been a resident of that city and he had houses there. But when he 
    migrated, Madinah became his place of residence. So if you go to visit your 
    family, you are a traveller.

    End quote from Liqa’ al-Baab al-Maftooh, 58/23 

    He was also asked: If a person travels and leaves his family, 
    and he has the intention of not returning to his homeland, and he stays in a 
    city that is far away from their city, with the intention of settling there, 
    then he goes back to his family for a visit, should he regard himself as a 
    traveller or not? 

    He replied: If a person leaves his original home with the 
    intention of settling in a different city, then when he goes back to his 
    original home he is a traveller, so long as he still has his original 
    intention (of settling in the second city). The evidence for that is that 
    the original home of the Messenger (blessings and peace of Allah be upon 
    him) was Makkah, but when he conquered Makkah he shortened his prayers, and 
    during the Farewell Pilgrimage he shortened his prayers. 

    Questioner: Does this apply even if his wife and children are 
    in the first city? 

    Shaykh: Yes, even if his wife and children are there. 

    End quote from Liqa’ al-Baab al-Maftooh, 82/23 

    For more information please see the answer to question no.
    121637 

    And Allah knows best.