Hi
Welcome to HM.
Most of the time it is psychological.
You have done investigation to rule out organic cause.
Be relax
throw all material from your mind
Masturbation is normal physiological function of our body
It is one the method to satisfy sexual pleasure in absent of partner
both sex and masturbation has same and has same end result to get satisfaction.
So excessive think can cause psychological stress.Constant thinking and feeling of guilt of masturbation will effect
So no need to worry.
Regarding
premature ejaculation.
Your
anxiety and stress will affect your sexual functions
Sex is mutual act.
Premature ejaculation can be treated with both psychologically and drug therapy
psychological means
to learn how to stay long
Certain methods like women on top position,condoms lubricated with
benzocaine kegel's exercise will helpful .please read on net and learn how to do it
Stop and start method of sex is very good results. it is thought diversion method and require time to learn . search on net to do it proper way
read more on google
Masturbating before sex can increase your time
proper play and understanding is needed
Condition can be treated with medicines like
dapoxetine and mild dose of clomipramin if require.
Thank you.
Happy to help you.