How often should you have sex when ttc?

At the beginning when I was ttc my partner and I would have sex mostly everyday or sometimes 3 times a day. It would be every other week or every other day or 2 days and I'm still not pregnant. I only had sex 3 times out of this whole month because he was sick and my period just showed up. It's been 13 months of trying and no baby yet. I don't track or anything cause it just brings me stress. Is it ok if it's every 2 days? My doctor told me it doesn't have to be everyday.