Hi Christiane,
Online sites are great for getting information about conditions and issues, but it can not take the place of your husband's doctor. If you think he is having a serious issue you should make an appointment.
There is a condition called Retrograde Ejaculation where the man can maintain an erection but either has very little ejaculate or none at all, called a dry climax. You can read more about Retrograde Ejaculation here.
Hope this helps. Make sure you get him to get a check up and let us know how you are doing!!Best,
Vicki M