I get erectile dysfunction once in a while. Is it due to physical or emotional cause?

Hello doctor,

I am 30 years old. I have erectile dysfunction. I do not know whether it is due to physical or mental cause. I eat very healthily. I do not smoke or drink and exercise around five times a week. I quit porn about six months ago. I have morning wood, maybe only once a month, and it does not stay long. I broke up with my ex-partner a year ago. I had no problems getting a bond with her. Only like 1 out of 20 times I had a harder time maintaining an erection. Only my libido was going down after we have been together for about two years. But with my new partner, I always take some viagra to be sure not to have any problem maintaining an erection. Even if I take 1/5th of a tablet, it is enough to have nil problems and having sex two times in the night. But when I try it without it, out of six times, three times we had successful sex, and the other three times it went soft.

I am now out of the country for several weeks, and I am starting to think this is a physical issue and believe I cannot maintain an erection. Even if I masturbate without porn, I have a hard time maintaining an erection. But on the otherhand, once in the week I think about sex and get an erection that stays without a problem for 15 minutes. I am very confused, and the reason why I believe this is a physical problem because I barely get morning woods and my libido is very low. I want to have that feeling from 10 years ago where I could have sex easy every day without a small amount of Viagra. Also, I have a numb feeling in my penis for the last few days. Please help.

Thank you doctor,

I have tested negative for diabetes and not using any antidepressants. I will test for testosterone in a few weeks when I get home. Can I conclude that it does not have to do with my nerves and blood vessels since I get a good erection once in a while?

Also, when I use Viagra, even if it is just 1/5 th of a pill, I enjoy the sex much more and I am more aroused because I know it will not be a problem to get an erection.