“I'm in the middle of a divorce. Fortunately, my husband and I managed to agree on the terms of his ruling. The husband stood up with honor and decided to move out, leaving my apartment to me and my children. I took care of them almost on my own, so according to later arrangements, they are to live with me. But I do wonder, is this solution correct. It would certainly be easier for the husband to find himself in the new situation, if the older son had stayed with him. They have so many common interests, likes, they are emotionally attached.”
Idea – I believe - it results from feeling guilty towards her husband, who surprised you with his compassion and generosity.
Perhaps such behavior is justified by the reasons for the breakdown of the marriage, which are unknown to me. However, this is not relevant for decisions about where the children live and how to appoint a guardian. After all, they cannot be treated as parts of common property - next to the apartment, car, wardrobes. Breaking down the parents' marriage and losing daily contact with one of them is painful enough for the children, to deepen them by loosening contact and bond with siblings, change of place of residence and surroundings.
If sons are related to each other, and the Lady is a primary person for them, fulfilling most of the care and upbringing obligations, it seems like a crazy idea to consider dividing the children. You should solve the problem of guilt in a different way.