I think in that last line you meant "we're." It is indeed a sad poem. Relationships happen and then they end. It's just the cycle of how things go. As the French say "C'est la vie." Don't blame yourself. It's difficult to find someone that grows in the same direction that you do. Don't ever think that you're not worth the person you're with because it simply isn't true. If someone is making you feel this way then move on. You'll find someone who appreciates everything you've got and what you are. Don't settle for anything less!