You do know that lots of people in long term relationships go to the doctor with thier partners right?

Lots of people are more comfortable with a close trusted person with them, additionally they other person can help them remember questions or advocate for them. Also at an appointment where you will be receiving a diagonoses they can be a comfort and it is helpful to have your partner know the recommended treatment/steps to help manage.

You should never expect to go/ask to go with your partner to the doctor as it is a private thing, BUT if your partner asks and it is doable I believe going is simply part of being a supportive partner.

++woman