If a married couple, in their early stages of their marriage do not define how they are going to live their lives, especially with their interaction with each other's families, then there will be many ongoing problems.
Defining your relationship with your family, and your in-laws, is very easy, even if they might be difficult to deal with.
Your primary position is your obedience and loyalty to your parents. This is the Islamic principle, and that's how you live as a Muslim. Even if it means you are uncomfortable, or it isnt really what you want, but if it makes your parents happy, then that's what you should do.
As for your parent-in-laws, they are now like your parents, so you treat them as you would treat your own parents.
This is applicable to the husband and to the wife, equally.
Let's be less sensative, and more accomodating to them as elders, from a different generation, from a different mindset. And all for the greater good, of keeping peace and harmony.
Imam Ja'far al-Sadiq (a.s.) says: Do good and obey your parents so that your children will do good and obey you.
I've also come across a tradition about how cursed a spouse may be if they were to force their spouse to choose between them and their parents.
Of course parents are more important. Not just more important that our spouse, but more important than ourselves.
What if the husband/wife has no consideration, and cannot combine between their family and their parents. This is why it is so important for us to learn Akhlaq.
You should never allow yourself to be in the situation where you have to choose between your spouse or your parents. You should also never put someone else in such a situation.
Balance happens when you respect boundaries, and as I said, you have defined your relationship. You pay utmost attention to your husband/wife, and at the same time to accommodate to the needs of your parents and family members. You also never discriminate, and treat your in-laws the same.
You have your own life now, and you are trying to build that, but you wont be able to create a loving caring atmosphere at home if you break bridges with others. That's why we shouldnt think that way, who is more important you or your parent, or who do you love more, your son or your daughter and so on.
We accomodate to each person around us in the befitting way, based on shar' and akhlaq.
With prayers for your success.