I'm worried that your erection difficulties may be related to a more serious problem going on with your diabetes. The fruity smell that your girlfriend is probably smelling is likely ketones - usually these are related to very high sugars though it sounds like yours are quite brittle. Is there any chance that your meter may be broken? do you have urine ketone strips that you can check with?
Why has it been so long since you had a HgbA1C checked? The usual standard is every 3 months.
There is a condition called euglycemic ketoacidosis (see question 8 on this:
http://www.postgradmed.com/issues/2001/11_01/carroll.shtml )
Although this doesn't quite fit with what you've told me, I am still quite worried. I would recommend visiting a physician and asking them to check a urinalysis for ketones, and perhaps confirm that your meter is working. Ketoacidosis can be a reason why people can have erectile dysfunction.
Do you have a clinic that you can go to?
Doctor (MD)
9 years of experience as board certified internist, pediatrician. Specialize in Adolescent Medicine.
The change in semen may also be caused by dehydration or changes in your normal blood salts and sugars. An STD would be a possibility, but I would expect a different spectrum of symptoms.
Are you taking any medications for the sinusitis?
Here is another article on euglycemic ketoacidosis. It was not something I was well versed on, so I've been reading up on it:
http://www3.interscience.wiley.com/cgi-bin/abstract/85514741/ABSTRACT?CRETRY=1&SRETRY=0
I would encourage you very strongly to have the urinalysis, and perhaps get the doctor to prescribe you ketone strips for your urine. Correcting the condition should fix the erection problems.
Let me know what you find out -- I'm a little curious now too.
Dr. Eric