Anyhow, when I think of a relationship requiring work, I think of one or two of them being aware of a sticking point between the two of them and making changes or adjusting themselves so that the relationship can flourish. For example, your partner may be a comedian that's in the process of trying to make it big and you are a businessperson who thinks of being practical and getting ahead in life. Both of you seem to have different life directions/goals. For the relationship to work, there needs to be an awareness of it and changes of some kind, say changes to your/your partner's/both of your mindset, spending pattern, etc. These changes are what I meant by adjustments.
Let's see how much adjustment is potentially needed for Capricorn in a relationship with another zodiac sign a.k.a. Sun sign.
Remember, the above is just one of the many elements to a successful relationship. Every relationship is different and special and can certainly work if both of you wants it bad enough.
All the best,
Joseph