Answer: Alternative family relationship
Step-by-step explanation:
Alternative family relationship is one of the type of non-traditional families where they share their common living expenses, house and also the overall cost of the housing.
The two different families are start living together and share the common interest, resources so this type of families is known as the alternative family relationship.
According to the given question, the two single mothers are busy on their social lives so they decided to shared the house three years ago so based on the given scenario this type of family is represent as an alternative family relationship.
Therefore, Alternative family relationship is the correct answer.