My boyfriend and I have been together for almost 10 months and have been sexually active with each other for 9 months. We were each other's first and only sexual partners. We have never had any issues sexually and have had a pleasurable sex life. We have sex multiple times per week and are very open with each other sexually. We discuss our sex life with each other at ease.
One day last week we were going to have sex and we were fooling around fully clothed under the covers and his mother knocked on the door and came in and when she left, he could not regain his erection. It was understandable and we moved on and it was not an issue.
This past Sunday, we had sex but it did not last very long as compared to normal and I did not get much pleasure from it but we did not have any problems or talk about it much because we were both somewhat tired. Last night (Monday) he was seemingly very turned on so we began to have sex and not far into it he became soft and could not get hard again. I was very upset and he explained that it had nothing to do with me and that he really wanted to and didn't know why this happened. He ended up manually stimulating me to help relieve my frustration. Tonight we were both very turned on by each other and frisky all evening and tonight we were talking about sex and what we wanted to do etc. and then I noticed he wasn't acting on it and I noticed him look down in his shorts and then kind of hit himself in the head and sigh. He did not say anything but I knew there was something wrong. I excused myself to get a drink and when I came back to the bedroom and laid down I asked him if he still wanted to have sex and he said he wanted to but he didn't know what was wrong with "him" meaning his penis. I asked him if he wanted me to try stimulating him and he did not respond and just said that he didn't understand what was wrong. I got very upset again and he assured me it had nothing to do with me and that he was very turned on by me and didn't know what was going on. He insisted that he could not think of anything that would be stressing him or causing him to not be able to perform.
I do not want this to keep happening. Although we love each other very much and plan to be together for a very long time, perhaps married one day, we have had our ups and downs and have the occasional discord. I am worried that this will make us less close with one another. Help?