Child maintenance from my husband to his ex, i feel its too much

My husband and I is married for 8 years. We have a child together. He have 2 kids with his ex. Now she is married again and staying with her husband and her kids with her. My husband want to go to court to decrease his maintenance. He don;t earn much but she wants close to half of his salary. Whereas our child's maintenance is not on time. Meaning: his boss deducts the child maintenance for his ex from his account. which means she gets her money before his salary is even paid in. The thing is its always a struggle to get a pay slip from his company and he is too scared to ask for it. For the past 8 years he just talk about it but never get to that point by doing it. i feel its unfair, these past few years, there are times he do not get to paying our daughters creche and now school fees or even buying her goodies for the month. I feel its just so unfair. so the question is, i feel he pulls her first and i as the present wife have to suffer. at this stage i feel he will make no effort to do it and at times i feel to just divorce and know i can make it on my own. i spoke to him about it and many times it ends up in an argument. Also , i know one can go to court and apply for maintenance in your marriage but i do not wish to go there as i know it will cause a lot of complications in our marriage. if i was in his shoes, i wouldve done it long time ago and would not want to hurt my wife and see to all my children, fair and square it just frustrates me that do nothing about it.