I think both Helper 015 & Savedslave have some good advice. Could be a slight physical problem, if so, then ED meds like Viagra or Cialis could help. Sometimes guys just lose confidence & need a little help from one of the ED drugs & then get their confidence back & no longer need it. Could also be a bit of a psychological issue - most guys will eventually have some sort of issue at some point & it freaks us out, then the more we think about it, the worse it gets. And always possible there's a little bit of both. I happen to believe that the mind has a powerful influence on our sexual responses, and sometimes any doubt at all creeping in can just cause all kinds of problems. Also possible it's a little of both. See a good Dr. (preferably either a Urologist or one who specializes in ED issues), hopefully he/she can get to the root of the problem...
I have the same problem. I know that for me its because I am thinking too much. I worry if I am soing itbright or if ahe feels good or I worry about going soft. Things that help me are talking tonher during sex. Gets me out of my head. Telling her how good ahe looks or smells or what feels good.
Hey, sorry to hear about this situation. A good thing is that you get hard (enough for penetration, right?) (before you eventually lose your erection), which shows that your penis can fill with enough blood etc. It may be a matter of losing the blood once it is in there. It's possible drugs like Cialis or Viagra will help you maintain your erection. There are also other medical interventions that could be attempted depending on what the source of the issue is. If you find a good urologist who could check that out, that'd be good too. I would cut out masturbation as much as possible, and also be mindful over how you masturbate. Masturbating wrong can cause internal injury. Can you think back what may have happened a year and a half ago or so - anything injury related? Do you take any medications, where this could be a possible side-effect?