I'm sure it was because I applied for a great job so didn't *really* want to get pg that month so I wasn't stressing about it. Although in saying that, we BD'd every 2nd day after AF and a few extras around ov time (our wedding anniversary). I also had PreSeed in the cupboard as a plan of attack next cycle
So yes, my advice is; don't think about it too much (impossable I know!) and BD every 2nd day