There are issues and causes that are important to each of you, issues that you've dealt with or causes you've championed for quite a while before the possibility of this relationship ever came up. That fact makes it difficult to deal with the fact that you aren't very supportive of each other's causes. There is a lack of understanding between you, and really, a lack of respect.
You just aren't able to see the truth behind each other's important causes; your partner, for example, looks at you through jaded lenses, and probably thinks that you're just being rebellious for the sake of rebellion itself. It stinks not to feel supported or respected by your lover in all the things that are most important to you. You might start to feel as if you have to hide your activities regarding certain areas of your life, just to avoid criticism or ridicule, or even just the subtle, slow disappointment of being misunderstood. If plenty of other factors are more in place and harmonious between you, then by all means, try to work this out. Make the effort to understand what's important to your lover and why, and to communicate your own important issues. If there are other aspects between you that make communication or mutual understanding difficult, you might just not want to bother.