What Could Sudden Onset Of Erectile Dysfunction Indicate?

I m 36 never had any issues with ED, actually mischievously known of getting boners every often. For play was something I read on books - never needed for erection, unless partner insists. I d get erected just by the thought or seeing her naked. I d normally go forever doing it - once lost a girlfriend through taking about 1:15 minutes non stop bonking - only changing positions in the process. Well not until the past three weeks after I dismally failed penetrating an unsure virgin. Next thing it got soft immediately I put it in my girl friend s vagina (the usual, not the virgin) . We ve tried four times since then and same story, I can t hold erection for a mere 60 seconds, that is if and when - after several attempts of trying to get it up - it ultimately awakes. This scares me and confuse me. I m as healthy as a greenbean, did BMI check up last week everything sugar, cholesterol, temperature etcetera fine, no stress nothing. What could be happening and how could I fix it. It can t be black magic from virgin, who now has dumped me for having allowed me to dare even see her naked, she s a devoted saved Christian. And hope tell it s probably not her prayer s (curse) effects.