There can be erectile problems in Men. The causes of the problem can be any number of reasons. It can be a physical problem. But sometimes the problem is due to Psychological reasons.
Take an example, suppose that a man has alcohol on the night of the sexual intercourse. He may not be able to attend or concentrate on sex leading to non erection. On the next night he may have the fear again and that fear may lead to the problem. The problem may occur sue to various psychological reasons. Fear, nervousness, lack of concentration, tension and a number of other things. If the mind is too much on other things then arousal levels will be low and can be one of the reasons for the problem.
There are a number of psychological reasons resulting into male dysfunction. It may be because of the work pressure which leads to a lot of stress and your concentration may be wavering. The other causes can be depression as a result of some problems in life. You may lose interest in sex as a result of depression. Psychological traumas can also affect sex life. All these interfere with the brain function and your brain does not get sufficient stimulus for arousal. Sex is a positive feeling while depression, anxiety and worries are negative feelings. All these inhibit the feelings and emotion attached to sex. If you continue with such feelings for long then it may interfere in your normal sex life for a long time.
The fear of performance in sex is also one of the reasons. Also one needs to understand that at different points of time in life, the body behaves differently. If you are advanced in age it may take you longer to get an erection.
The dysfunction due to some psychological problems is normal and you need not worry about it. You should try to get to the root cause of the problem, understand it and then proper measures to get rid of it. Remaining positive and energetic in life is important. If the problem is more acute then you can go to a psychologist.