Not for a second. And while I was deeply unhappy and pretty much just existing and wasting away in a horrible marriage, I didn't actually realise how shit and wrong some of it was until long after I'd left, and even more so when I met my now DH and started to enjoy a "normal" relationship.
You can never have any idea how people will react when a relationship ends and for most people it's only then that you see who your ex really was - mine did not cover himself in glory and was even more of an epic shit than I could ever have imagined. Confirmed that I'd made the right decision many times over.
Are you happy? Does your partner and your relationship make you feel good, respected, cherished, looked after, loved, appreciated, valued, optimistic about the future? If not, you can leave. There's no law to say things have to be a certain way in order for you to decide the relationship isn't right for you.
If you're thinking about it this much it must be eating away at your soul and exhausting. Can you imagine things being worse if you were apart? Or does the prospect fill you with hope and optimism?
No one said leaving is easy, but in the long run it's a damn sight easier than trying to survive a relationship that doesn't make you happy.