I wonder if Milk is setting up a conflict about the frequency of sex down the road. It seems like Rena has a pretty high libido while Yuna's is not low, but probably closer to "normal," whatever that is. I'm sure there's some "new relationship energy" going on, but if Rena is ready to go at it three times a day now, I wouldn't be surprised if she's still down for several days a week once things settle down. To be honest, I'd kind of like to see it be a point of contention. It's not something you see often in fiction and would be more interesting than a jealousy plotline. In fictional media unhappiness about the frequency (or lack) of sex is usually implied to be a symptom of larger problems in a relationship. In reality, disagreements about sex a very common sticking points in relationships.