Ok. I haven't experienced something like that, but here's my piece of advice, from a jealous... or normal wife point of view.
If you're married, and you get excited getting examined by female doctors, you should try to get male doctors whenever possible. It is a form of cheating if you're getting female doctors because you like getting excited by them. No wonder your wife gets upset. She sounds like she's onto you.
Also, you shouldn't be concerned with 'impressing' them. This meaning, you WANT them to see your penis erected? otherwise it's not impressive? This sounds even more wrong. You shouldn't want them to see you like that, and not just because they might say it's inappropriate. It sounds like you ARE trying to live out the fantasy, you're not cooperating for it not to happen because, quoting you: you like it.
Even the 16 year old here can see that, i would like to think a fully grown and married man would take his marriage more seriously and discern what's acceptable behaviour and what's not.
How would you like it if your wife only got male doctors, not because they're good doctors, but because she's turned on by them?
My advice to you is to stop putting yourself in those situations, and if you like the nurse's outfit that much, start roleplaying with your wife and dress up as various things, including her as a nurse or sexy doctor.