How can I stop recurring abscesses?

This sounds like hidradenitis suppurativa.

http://www.nhs.uk/conditions/hidradenit ... ction.aspx

It isn't curable but it is treatable -- best to talk to your GP about what treatment options would be right for you.

I would always say Keep that blood glucose DOWN. Infectious organisms LOVE glucose, so if you feed them , they flourish. In addition, in the groin area, improve your toilet hygiene, even if it's already good. Perhaps use wipes as well as loo tissue and tea tree products. then keep the area dry.
Ask your doctor or practise nurse to help. I was trained as a microbiologist and prefer the use of asepsis and antiseptics to antibiotics. Using antibiotics helps drive up the incidence of antibiotic resistance.
Hana

It's worth noting that hidradenitis suppurativa is not caused by poor hygiene and not exclusive to those with diabetes. It's suspected to be the result of a hormone imbalance, much the same as acne, and that there is likely a genetic predisposition. Women who have it will generally find it gets worse just before their period.

In the majority of cases the only bacteria that can be found in the abcesses are the healthy bacteria normally present on the skin. Antibiotics will help control secondary infection, if present, and other avenues of treatment can help resolve or reduce the cause. It is an unpleasant and painful condition and any treatment that helps is worth trying.