Generally people struggle when there are changes. It hurts when you see changes in partner. It hurts when you see changes in kids. It hurts when you see changes in friend. Why?
Key point is, you dont know the difference between behaviours and charecters. Behaviours are the visible actions. They depend on the circumstances. Example: you wear saree if you are staying in India. You wear suit if you are staying in London. Behaviour is influenced by culture, society, people and knowledge. On the other hand, charecter is set of morals and belief systems which never changes. Example: helping nature, courage and frankness.
When you see changes in partner, first you have to observe whether they are behavioural changes or not. If they are behavioural changes, they can be accepted. They are temporary and they depend on environment. If you see changes in charecter, that means you are understanding/ knowing your partner’s old charecters now. You never understood or found them before. If you cant accept the charecters, then there is no point in holding relation. No charecter can be changed. But many people, especially women live in a notion that they can change their partner.
Similarly, if you see changes in kids, verify if they are behavioural changes. Your kid belongs to another generation and another time zone. So their behaviour will change over time obviously. But if you think that there are changes in charecters, that means you have never understood your kid before. Try to understand them and accept the way they are.