Its a shame if you have caught old sores / herpes simplex from your husband as there is no curing it.
I also often get cracked corners of my lips in the cold weather, every so often these can get slightly infected and are very sore and look quite a bit like cold sores. I pop a bit of steroid cream on and this always sort the problem out in a couple of days. You can get some over the counter at your pharmacist.
So it might not be a cold sore, that said a drop of Zorivax won't do any harm so probably best to give it a go first - hope it clears up nicely for you