This is from Spark Notes
Many people use than when they mean then, and vice versa.
Than, a conjunction, is used to compare things.
Then, an adverb, is used with descriptions of time.
• Then, suddenly, Mr. Perez shouted, “I’m a better diver than you’ll ever be!”
• I think she looks dangerously skinny, but then, what do I know?
Seriously – how hard is this?? It’s 2nd grade grammar for goodness sakes. If you’re going to put yourself out there online – especially on forums where EVERYONE can see – why would you not THINK before typing. Use the right word. Otherwise grammar nazis, like myself, are going to read it, get irritated with you and think you missed that year of schooling.