Hello Izzy,

While online sites are great places to get information to be able to informatively ask all the right questions, they can not take the place of a doctor's solid medical advice. So if you think there is a real problem, you should encourage your partner to see a doctor.

Your question and your paragraph are two different subjects. your questions says;

Do men over 30 get unintenional erections during the day, or does it depend on sex drive?

There are times when a man will have an erection without being in a sexual situation. Most of the time this occurs at night. You can read about nocturnal erections (Nocturnal penile tumescence) here. Dr Jay Motola has also written about nocturnal erections here in this sharepost.

The second part of your posting deals with your observance that your partner is gradually having difficulty getting excited. This could be signs of erectile dysfunction. You can read the symptoms here to see if anything appears to apply. You can also read a good over view here.

Lastly, you asked what angle a penis should be at when fully erect. All men are different, whether it bends, points up or towards the left or right is different for each individual. Bending of the penis is not rare. You can read more about that here.  There is a condition where the penis points downward when erect called Peyronie's Disease. You can read more about that here.

Hope this helps you somewhat. Take care and stay in touch!

Vicki M