It sounds like your question is more "How do I not let my desire for sex get in the way of getting stuff done." and has nothing to really do with relationships. A relationship with the right person would only increase your own creativity and productivity.

I guess I'm extremely fortunate to have a relationship with someone who encourages me when I feel worn out and wants to give up and who understand when I have to put in time to get stuff done. I'm a big believer that the right person for you inspires you to do better and makes you feel like you can achieve anything. I double my efforts because I want to create something of value so that we can both share and enjoy the things we want to do with our lives.