Even surgical abortions are substantially less risky than other kinds of surgery. The body cavity is not injured, and the patient doesn't have to be fully anesthetized, which removes the two most serious risks of surgery.
The majority of women do struggle with the decision, but ultimately feel relief after it's over and done with. And I would argue that if society weren't so cruel towards women who abort, it might be less emotionally taxing.
Also, abortion does not cause sterility. That is a myth promoted by the anti-choice community.
As to STD's, that kind of depends. Some STD's can transmit by skin contact, and leave both men and women very susceptible. And in a lot of cases, the affects on men have been largely neglected by science. For example, we have known for a long time that HPV can cause cervical cancer in women, but we are only now discovering that it causes anal, throat, and other kinds of cancers in men as well.