Ideally you should have had sex on the days just before your temperature began to rise, so keeping temperature charts can only give you a general picture of when your most fertile time might be, and tell you whether or not you're having intercourse near to ovulation. Ovulation predictor kits You can also buy ovulation predictor kits which measure the changing levels of hormones in your body to help you work out the 'best' time for intercourse. According to an eminent infertility expert, one of the most common causes of infertility is infrequent sex at the best time of the cycle. Your partner will not 'run out' of sperm. Sperm counts are slightly lower if a man has frequent sex, but since each ejaculation contains millions of sperm this will not affect his ability to produce sufficient sperm.
Pregnancy is a matter of chance.
It does not always happen even if the egg and sperm are in the right place at the right time, and the length of time that it takes couples to conceive varies a great deal. The chances of getting pregnant in each cycle vary according to a wide range of factors, but perhaps the most important one is the woman's age. Given the chances listed above, most GPs tell you not to worry until you have been having regular sexual intercourse without contraception for at least a year. Only then does it become more likely that there is a reason why you are not conceiving and this can be investigated. If you are reluctant to see your GP just yet, it may be worth starting to keep a temperature chart, as this is one of the first things your doctor is likely to ask you to do if and when you do go and see him.