Pre-nups are something that has to be well thought out and and definite sometimes. Money is something that should not be messed with and be taken care of all the time and when you get married you have to make sure the union will be stable enough so that the money can be managed. Some people don't believe in pre-nups because of some religious aspects to it being that it can mean you are signing yourself into divorce. Others feel it is necessary because they don't want to split their money for anyone. Others feel whatever happens, just happens.
There is also something called a post-nup which is something you sign after getting married. Some people may find that offensive because it's almost like a second thought decision like "Wait I don't want my partner having my money, let's change up the situation!" It could make some people question the relationship because it can look to the other person like they feel they are not trusted. This is why rushing into any situation can be cause a lot of misunderstanding and miscommunication because when it comes to money, that should be the first thing to be saved and figured out.
Here is a clip about pre-nups on the show "The Real." watch the ladies as they discuss their views on the subject: