Thanks for query,
First of all remember that sex is in our mind & not in organ.
If you do not make up your mind for sex you do not get enjoyment.You feel it as a boring act.
Tension free mind,no anxiety
creates parasympathetic stimulation leads to desire of sex.So leave all worry.
The affection towards other partner also plays important role for sex enjoyment.
Imagine during sexual act that you are are the only person in world having so much happiness. Or your loving hero,or loving person will improve the experience.