Believe me if you are worried about running out of sperm, you've got another thing comin. (NO PUN INTENDED)
The only thing you really have to worry about (as far as I know and understand, I'm NOT an expert), is maybe soreness or getting raw. Being a woman, I know I can get sore after x-amount of sex in a day. But if it's not bothering you or her, then go for it!
Everytime you have sex though you are increasing your chances of disease or pregnancy. But if you are both tested and using contraception, then you shouldn't have anything to worry about!
You're just crazy for each other and extremely horny. Bless mother nature for sex! lol