Why i have trouble maintaining my erection?

Health "barometer": Erectile capacity is a "barometer" of a man's physical and/or mental health. Is your difficulty "situational?" does it seem progressive. How long have your symptoms been evident? Do you I have any significant health issues (eg diabetes/htn/cardiovascular disease/....)? Onset/progression associated with ("new") medication? Depressed/fatigued? Too many questions need to be answered - see your md.

Hard to say: In reality the possibilities are quite numerous. Without more information about your health in general along with the circumstances about when your issue came about, it's difficult to guide you in any meaningful fashion. Consider either formal consultation through HealthTap Prime or reviewing this issue in person with your primary care doctor or a urologist.