Now I'm curious. Doing a bit of googling and this is what I've found:

Conception Myths
Having sex too much and masturbation can lower your chances of getting pregnant. While technically if a man ejaculates too frequently his overall sperm count in subsequent ejaculate will decrease, meaning less of a chance of a sperm reaching the egg. However, men can replenish their sperm count within two days, and one study found that couples who had daily intercourse had the highest fertility rates. Cutting out masturbation on the part of dad-to-be may be a good idea, but sex every day shouldn't hurt your chances of conception.
Myth: Having sex every day will increase our chances of conceiving.

The truth is that timing sex during the most fertile days of a woman's monthly cycle will increase your chances ? not how many times you have sex. Generally, the best time to try to conceive is during the 11 - 17th days of a woman's menstrual cycle based on a 28-day cycle. Since a man's sperm can live for 48 - 72 hours in a woman's reproductive tract, intercourse every other day during this period is recommended. A study found no difference in pregnancy rates between couples that had sex daily and those who had sex every other day.[1]
Whether or not you need to have sex everyday in order to conceive depends upon a few things. If it has been determined that the man has low sperm count - it would be best to practice the every other day intercourse - or to wait until the day before the expected ovulation. If there are no problems with sperm count - it would be perfectly okay to have intercourse every day. This depends on your stamina, preferences and determination. If you pretty much know when ovulation occurs every month - it?s only important to have intercourse the day before or the day of and the day following - in case there is another egg released. However it may increase your chances of conception to do so more often.
Can having too much sex affect our chances of conception?

Expert Answers

Sherman Silber, fertility specialist

No. While many couples believe they have to save the man's ejaculate until the exact moment of ovulation, that's not true. In fact some couples become so obsessed with timing sex during ovulation that they actually hurt their chances of getting pregnant. Stressing over ovulation can wreak havoc on your cycle ? not to mention your marriage!

It's a myth to think you should have less sex in order to conceive. All the evidence shows that the more you have sex, the better your chances of getting pregnant. In fact, having sex often ensures that the sperm in a man's ejaculate is as healthy as it can be. Storing it up can decrease its motility, so don't be tempted to put off intercourse until you ovulate, and don't abstain for more than seven days in a row. While it's true that the density of sperm in each ejaculate diminishes with frequent orgasms, all that really matters is that there is some sperm in the woman's fallopian tubes during the time of ovulation.