By God's wishes, your parents need to see a counselor. When they look for a counselor, make sure they find the best one, the one who understands the whole concept of True Love, fully. For example, someone with a faith background, like a priest, someone who understands a divine concept like True Love, because True Love was created by a Divine person: God. Many counselors cannot help people, they just want your money, because those counselors themselves do not understand the concept of True Love the fullest, a perfect concept/ way of life that covers all aspects of life, all the ultimate concepts:"How to be Romantic, True Happiness, True Marriage, True Relationship, True Parenting, True Friendship, True Purpose of Life, True Leadership, True Faith in God, and Kingdom of Heaven”. True Love concept is flawless in design, works perfectly to bring a couple, any man and any woman, to a more mature, more unselfish, more complete/ powerful/ happier and wiser state, regardless of their differences. It takes constant work to make their marriage work and happier.
Part of the problem is this too: your dad doesn't know how to solve his marriage problem, because he practices Self-Love. As a husband, if he knows the concept of True Love, the fullest, he should be able to make your mom understand and not sad. If he understands/ practices True Love, he would have a True Purpose of Life, which is to live for you and your mom, for the True Happiness of both of you, and he would understand that True Marriage is this: to complement/ help each other to become more mature/ unselfish/ compassionate/ passionate/ purposeful/ romantic/ wiser. That includes comforting your mom when she is down, being compassionate (understanding what your mom or you are going through), understanding that when he and your mom separate/ divorce, the divorce might create a personality disorder on you, or confusions about your future marriage/ relationships. When he leads your mom with True Love, your mom will be compelled to follow his footsteps, she would live for him too: she would strengthen/ comfort your dad when he is miserable. No, you are not selfish, your parents are the selfish ones.
By logic, there is no way that your dad cannot make your mom to become a better/ more mature/ more unselfish person, and vice versa. The proof? Here is the logic/ proof. It's like asking this question:"Will a person be selfish, childish, or a bad person for the rest of her life?". God created humans to have the capacity to live, think, act, love, like God, so they can be as complete, as happy, and as powerful as God (very close)-all the very reasons why we were created in His image. So there is no way that God cannot solve your parents' marriage problems with His perfect concept of True Love. Don't your parents know that, when they married each other, they were supposed to have a True Purpose: to live for the happiness of their future children? Don't they know, the whole purpose/ idea of a True Marriage is about complementing each other, to become more mature, more unselfish, more compassionate, so they can make their children be like them, so they can be the happiest and most complete as human beings?
Your parents' marriage problem is actually a universal problem. Most people in the world don't understand the concept of True Love. They think they do. But in reality, they don't. The proof? The divorce rate in America is more than 50%. What does that tell you? They understand more about this other concept called "Self-Love". It is the media to be blamed. The media (movies, books, radios, tv, magazines, newspapers) confuses people with the wrong meanings of True Love and American Dream. ”I think I have found my True Love”, or “I fell in love with her at first sight”. Even Jane Burns understands, in the movie ‘Dan in Real Life’:”Dad, love is not a feeling, it’s an ability”. True Love is not a thing, person or feeling; it’s a divine concept of living. Only from understanding True Love fully, and from living/ practicing it completely (an ability), can we truly enjoy the power of it (a divine feeling).
In the beginning, God created a perfect concept called True Love, as a manual for humans to live a truly happy life, for the use in finding and enjoying their divine state: as happy, as complete, and as powerful as God. Yet humans are lured into believing that another concept, called Self-Love, or Selfishness, would bring a higher happiness, or a more powerful state. In reality, the Devil, or the Fallen Angels, invented that Self-Love notion, to steal us from the very joy of life, whereas the end result is, we are tricked. Less power for us. Giving us a weaker foundation. Sadness, confusions (knowledge about relationships/ marriages), stresses, personality disorders in children, problems, loneliness, hate, jealousy, fights, violence, divorces, wars, etc. The derivatives of selfishness.
God bless you and all your family
There are two forms of custody, legal custody and physical custody. Unless the parents lives very close to each other, only one parent can have primary physical custody. You have been awarded sole physical custody, which means the children live with you at all times (Although your ex could have been given some visitation, supervised or unsupervised.) The other type of custody is legal custody. Joint legal custody means you have to consult with the other parent in making decisions regarding the children. You have also been granted sole legal custody. That means you never need to consult with the other parent about any issues regarding your children. Sole legal custody is unusual. You are obviously a superior parent and the Court has recognized that fact.