There’s multiple answers to this question. If the relationship between the partners is unhealthy, (yelling, abusive.. etc) the child could follow in their footsteps and start to act the same towards each parent. For example, if a child hears his father yelling to his mother and calling her names, the child can copy his father and in turn develop a very unhealthy relationship with his mother. Hope it helped. Message me if you need further understanding :)
