I have a friend who is in a bad marriage. I have talked to her about what I think since she was asking me for advice. I feel that in some way, I overstepped my boundary.
You don't want to make your friend angry at you by her thinking you are trying to split them up. What should you do?

This can be a very sticky situation, and it would likely also depend if you are a male or a female friend. It's hard to say the best thing to do with so little info.

I would tell her that although you really don't want to interfere, you don't want to see her unhappy or taken advantage of, because you value her as a friend. Also tell her that no matter what decision she makes, you will always be there for her if she needs you, but if she needs you to back off a little, that you will abide by her wishes.

Now this is unless she isn't in any imminent danger of any kind. If she's in danger, then you just might have to risk your friendship to try and get her out, because that would be a dealbreaker!

Again, with so little info, it is hard to give any specific advice to you.