Herpes simplex one on head of my penis? Not sure who gave it to me, but should I confront the one with cold sore?

Herpes. Herpes is a viral infection of the skin. It always comes the first time from another person. Herpes on your penis could come from your penis contacting the virus in a woman's vagina, or a persons mouth or anus, or even their hand. It doesn't pay to confront anyone about where your infection came from, and you should use condoms for sexual activity. Herpes can be treated easily with pills, or cream.
Do Not Confront. Since you are not 100% certain, and since at least75% of population have SHV Type I, it would server no positive purpose. You say you are 36, you could have had it for some time and it be dormant and just now showing up as well. HSV-I and HSV-II are both very common. Be aware that protection will reduce chances of getting HSV-II (less common) but is not 100% effective either.