Many causes may contribute to erectile problems, but fear of failure often plays its role.
If after one ‘failure’ you expect it to happen again you may start to focus on your penis. Like an outsider you look on to see if it will work this time. Because you are not paying attention to things that normally excite you, you don’t get aroused and won’t get a hard on. Every time this scene repeats itself your fear of failure increases.
One way to break this negative cycle is to redirect your attention. Kiss, hug, caress your lover, but keep your clothes on. Then you don’t have to worry about getting a hard on: nothing special is expected of you. Instead of focusing on your penis, you’ll pay attention to things that excite you. The fear will vanish and your erections will return.