I am 32 , no major health issues. i have no problem getting my penis hard , i have great trouble keeping it hard. this has always been a problem. what should i do ?

Find the cause first: To assess if one's erections are weaker than normal, he should visit his primary care doctor, who can check for possible causes: stress, depression, diabetes, high blood pressure, low testosterone, arterial disease, high cholesterol, smoking, etc... Causes found can be treated to help make erections stronger, firmer, longer lasting. A urologist can evaluate. Psychologist can sometimes help.