Divorce laws can be complex, and what they say can often seem unfair to one party or other, especially from within the emotional heat of a broken relationship. Some things that can seem unfair, but really aren't:

• "Wait, they get the kids, AND I have to pay them? I want my kids!". Child support payments are payments to support the child - it is fair that they go to the parent who the child lives with more, and it is fair that they come from the parent who earned more - though this can certainly seem unfair.
• "I earned that money! Why should they get a share?" The law regards married people as equal partners in a relationship. If one partner quits work to look after the kids, and that means the other can focus on their career, then it is perfectly fair to share the finances equally - or even force the earning partner to provide spousal support while the non-working partner tries the difficult task of getting back into the workforce after a 15 year break - though this can certainly seem unfair.

Divorces are more expensive, and take more lawyer time, when the parties disagree. Since their marriage just broke down, they often are not in the mood to agree on anything much. There'll be a lot of anger and hurt. In the end, both parties will have to agree on something that feels satisfactory to neither, and it can take time to accept that and let the lawyers just do their job. If one partner rants for half an hour to their lawyer about how bad and unreasonable the other partner is, there's no reason the lawyer should not be paid for that time, but yes, it is a waste of money.

If they come before the court and say "here's what we've agreed," that's a lot cheaper than paying a judge, bailiff and both legal teams for the time to argue why the house should be divided 40/60 instead of 50/50. But agreeing beforehand on a painful (for both parties) compromise can be difficult.