Most Helpful Guy
Every situation is different, but you two have sort of an odd relationship in that you see each other so infrequently. If I understand correctly, you two typically go about 10 days between seeing each other and last time didn't communicate for 20 days? That seems more in line with a very casual relationship than an actual relationship. To me, this seems like the bigger deal than whether or not you two should delay having sex. If you're wanting to make sure the relationship is real before having sex, then I'd first start with finding a way to see each other more often. Do you two live very far from each other or something?
Most Helpful Girl
From the question and the updates below it doesn't seem like he's interested in a relationship. Just the occasional sexual tryst when you're both available.
If you want more either lay it down in plain terms or move on