All I can tell you is that I used 2smoke between 2- 2 1/2 packs a day and started vaping about 6 yrs ago and the difference is like night and day. Since vapor is just that--no burning/combustion as well as none of the MANY by products from tobacco. Being able to breathe and control the nic levels could be a cause of ED, I honestly don't know. Everything I've seen suggests vaping is by far the better choice, for obvious reasons. Not to discount ur girl's advice, but as someone with problems of my own, ask 10 doctors and you'll likely get 10 opinions. I agree with 99% of vapers that it's by far the better choice. I will say that since quitting cigarettes overall I do feel much better, and it's much cheaper and convenient. No smoke stink/stains, much less people mind, etc. Hope that helps you.