If you'll look at the code of the constructor you're using -
public SQLiteConnection (string databasePath, bool storeDateTimeAsTicks = false)
: this (databasePath, SQLiteOpenFlags.ReadWrite | SQLiteOpenFlags.Create, storeDateTimeAsTicks)
{
}
You'll see that it passes in a flag that instructs SQLite to create the DB if it does not exist.
To avoid this, just use another constructor -
public SQLiteConnection (string databasePath, SQLiteOpenFlags openFlags, bool storeDateTimeAsTicks = false)
Like this -
using (var db = new SQLiteConnection(dbPath, SQLiteOpenFlags.ReadWrite))
Keep it mind that this will thrown an SQLiteException if the DB does not exist.
Another possible solution would be to manually check for the presence of the file before opening.