Men who are nurses and women who are nurses do date and some marry. I do not assume you are not straight simply because you are in a particular profession, nursing, hair dresser, artist, or any of the other fields that have stereotyped men in them as gay.
You will find this is generally the accepted attitude of patients and staff in any given hospital.
You question is valid because it is a common fear. I am not saying that it is a perfect world. Men do face discrimination in many hospital with it comes to obstetrics in many hospitals (not all). It is recommended that men protect themselves (MDs as well) when caring for females so that false accusations of molestation are not brought against them.
I did know one male RN who was guilty of molesting women and went to prison. The way you protect yourself is with profound sensitivity to female privacy and dignity. Trading off certain sensitive task with a woman nurse where appropriate. Insuring that you are not placed in a situation where you could be accused. For example male doctors have a female present when they examine (particularly intimate exams) a female patient.
If you conduct yourself with respect and dignity toward others you will do well regardless of your sexual orientation or precieved orientation.