I think the Tantric/Oriental philosophies of sex is that ejaculation depletes the inner essence. Hence, the goal is to have as much sex as possible while cumming as little as possible. So you're likely well on your way to becoming a Tantric Master, natch.
I can only think that by holding it in, the sperm could be channelled into the bladder, which could cause infections. But if you havent had any so far, then I guess you are doing something right! Also, doing it that much and not cumming would make your balls full to bursting by the time your once a month came around! Must be like a rocket blast off?! :thumbsup: