It's true. If you think about the characteristics of open source and the qualities of a successful relationship, you will find a lot of overlap.
OPEN: You have to be open and flexible to make a relationship work. Going back to my favorite analogy in regards to open source software and proprietary software--proprietary software is like buying a car with the hood welded shut. Oh, you need to change to oil? Too bad. Buy a new car. If we aren't flexible and open to change--if our hoods are welded shut--it makes it extremely difficult to keep the (love) engine running.
TRANSPARENCY: Secrets ruin relationships. Need I say more?
TRUST: Without trust in a relationship, you will drive yourself and your partner c-r-a-z-y. You will always think the other person is up to no good and assume the worst-case scenario.
PASSION: Naturally, the open source way attracts the passionate, it attracts those that want to be the change. If you aren't passionate about your relationship, you will stop working on it, and from there the rest unravels fairly easily.
SELF-STARTING: Open source is for the ones who "walk the walk." You want change? Do something about it. If you are interested in someone and you just think about it, you lose.
COLLABORATION: A successful open source community is about teamwork and collaboration. The same is true for a rewarding relationship. You give and you take.
RELEASE EARLY, RELEASE OFTEN: In relationships we don't get it right all the time, but you can't stop trying. This is also true in the open source model. Then you build something stronger and better.
Add on to the analogy--I think it could go on for a good little bit. Happy Valentine's Day from one open source lover to another!