Experiencing Premature Ejaculation and Penis Colour gone dark

Hi, In past few years i have been experiencing premature ejaculation. I went to see the doctor numerous times but was told it is stress related.

My penis colour has gone dark compared to rest of my body colour which is light.

I believe it is something to do with the blood flow but not sure as doctor's don't know much.

I am deeply concerned. I have been married for around 6 Years now.

Before marriage I had no such symptoms and I have lived a healthy Sexual Single life.

Everything was fine for the first 4 Years of my marriage but then i started to ejaculate early, in fact very early.

Problem is so bad now that i ejaculate within seconds now which means i basically end before i start.

This is really stressing me out. My wife is concerned too. She is although very helpful but I don't want her to start complaining which can practically end my marriage.

Can i please get some help and advice over this and any comments about anyone else going through the same thing? Is there something i need to eat in particular or avoid something in life?

Thank You