My friend needs a lawyer so I'm thinking of taking the money my fiance and I have saved for our wedding and spending it to hire a lawyer for him.
Why, what happened with your friend that he needs a lawyer? I hope it's nothing too serious!
He needs the money because of his lowlife ex.
While it's nice of you to want to help your friend out with paying for his lawyer, you shouldn't use money that your fiance is planning to use for your wedding. You can bring the subject up with your fiance and see how they feel about your idea, but don't be surprised or upset if they refuse.
I'm just gonna take the money and use it on my friend.
That money belongs to both you and your fiance so you should not spend it without talking to them first. They have a right to be involved in discussing what to do with that money. Spending it without getting permission is the same as stealing since it's not solely your money.