Our Father Abraham

Shalom Rabbi, Rashi is accurate in the Torah (perhaps it has an earlier source) that Abraham did not look at his wife Sarah for years. And I was unable to understand what the point of this is, is materialism a bad thing in itself? I understand that only materialism that contradicts Torah values ​​and laws is bad. And what is the point of Abraham not seeing his wife even though it was halachically permissible? And we find no reason to be strict about it.