Sometimes parents SHOVE their children into marriages that they don't want and cannot commit to.
IMHO in desi community there is this rush to get the girls married as soon as possible . The parents start to stress out once their girls enter into puberty. They start to feel a crushing weight on their shoulder. Once the girl has done has bachelors degree to those parents it means that she is getting old now. This rush to get those girls married off ASAP results in many disasters.
I am only covering one of the scenerio you have pointed out.