Thanks for your query.Based on the facts that you have posted it appears that you have problem of Secondary Erectile Dysfunction
You are married and have two children itself indicates that you did not have problem of erectile dysfunction in psat.
This is most likely due to performance anxiety
. Following measure will help you to boost up your confidence and getting good erection..
1) Practice regular exercise for 45 minutes followed by meditation
for 1/2 an hour in the morning.
2) Take high protein diet rich in vegetables and fruits and Vitamin A
3)Take anti oxidants like Almonds 5-6 everyday..
4) Avoid alcohol and smoking
Please note that the penis becomes hard only on erection and becomes flaccid after ejaculation and also at rest.
Do not worry evry thing will be al right after a period of time.