Cant have any Relations due to huge Penis....help

Well no Jokes here but I am unable to keep or have a partner coz as soon as I get intimate, i get refused, turned down or partner moves on. Why ???

As im too big down there.

I even went to a specialist and they say nothing can be done as it will risk permanent damage.

Im too embarrassed to even mention but im like almost 14in fully erect and thick like a coke can with fat head.
What can be done to reduce size ???