My father does astrology as a hobby, and I can say one thing for sure.
There is no difference between astrology and fate. One's fate is written the day they are born, and a horoscope (when read accurately) tells exactly what will happen in fate. The horoscope is nothing something created by the astrologer. He is simply reading what God has already written.
When it comes to marriage, whether one's marriage will be a good or bad one is already predetermined like the rest of a person's life. Whether they end up having arranged or love marriage, horoscope is written and cannot be changed.
Why then do people try to control horoscopes?
When it comes to parents of the bride and groom, they just want their children to be happy so they try to find the best match possible. So whether it is arranged or love marriage, they try to match the horoscopes in the hope that their child has a good life.
However, if it is written in one's fate that they'll have a bad marriage, or they'll suffer the death of a spouse, or they'll suffer abuse in marriage, etc, then there is nothing parents can do.
The horoscope is not something the astrologer comes up with. It is fate as written by God, and a horoscope should be taken as guidance to lead life fruitfully, but if something is predetermined, then it is not the fault of the astrologer, or the parents, or the children.
Fate is determined by one's karma, so the best thing to do is to lead a good karmic life so that in this life, or the next one, we live a good life.