Yes you can get aids from only having sex with them ONCE. And for him cuimng in you doesnt make a diffrence, if he has it, there is a chance that you could have it It is actually illigel for him too have aids and not tell you before yous have sex ??I suggest you go to your doctor and get a blood test.. That tests for aids and HIV and a few other things, also getting a urine test, tests for alot of other sexually transmitted deseases..And i think it just takes about a week or so too get your results back..Its probably the best thing too do.Good luck. Hope you dont have itt..