Hi!
One thing to consider is that you may be trying too hard! TOO much sex can deplete a man's sperm count. I hate to ruin your fun, but you might want to back off to one time per day.
There are lots of other things to check out too. When someone new comes to me with your question, I generally check to be sure she's ovulating. I like to use ovulation predictors--those are like home pregnancy tests, and you can get them in the same isle in the grocery store. I also like to check her tubes with a study called an HSG. They squirt dye through the tubes and take an x ray. Finally, I like to check the sperm count of the other half of the equation, to be sure there is not a problem there.
Women with diabetes often have thyroid troubles too. So often they don't ovulate regularly. One way to know--do you have your cycle every month? If not, you probably don't ovulate all the time. Men with diabetes often have trouble with their sperm count. So you should probably start out with a visit to a gynecologist or infertility doctor.
Good luck!
Dr B
Generally, the best time to try to conceive is during the 11th to 17th days of a woman's menstrual cycle, based on a 28-day cycle. Since a man's sperm can live for 48 to 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 who had sex daily and those who had sex every other day. Hope this helps.