So did I and the Boss have penetration sex or just foreplaying?

I think they have. In the first chapter we see I on top of his master. And then in chapter two they were about to do it but the master stopped because of the scent on I. It just indicates that something has really hapoened between I and his master

I think the boss is a pedophile who’s been taking advantage of I and eventually gets bored when he realizes I is too old for his liking, which he realizes after noticing I can now sexually please a woman

I don't know if he is pedophile or what but I think he didn't sex "I" because there is something that special with "I" that stop him to sex with him though I don't know what is that.