I agree with Micah. Even the slightest fear could cause you to subconsciously desire for it not to work.
My suggestion is that you work it out in your own mind. Write in a stream of consciousness style, where you just write exactly how you think when you think it, concerning this relationship. Write freely anything that comes to mind not worrying about punctuation or sentence structure. Do this for as long as possible in one sitting. Don't rush and make sure you have ample time to do it. Then afterwards map out key points and decipher where these worries lie. Then work them out in your mind before attempting to do anything about it magickally.
For any spell to work well, you must have 100% desire for it to work. If your subconscious is working against you, you won't have that 100%