The European fact sheet for health professionals and a Public Health Agency of Canada Pathogen Safety Data Sheet both note the 7-week figure, the latter also adds a 61-day figure.[2,3]
The United States Army Medical Research Institute of Infectious Diseases (USAMRIID) Medical Managements of Biological Casualties Handbook (7th edition) notes a 3-month (~80-days) period, during which one should probably avoid sexual relations so as not to deliver virus directly to a mucosal surface.
Semen is therefore listed as one of the body fluids from which Ebola virus disease may be contracted.
While convalescent patients seem to be discharged before 7-weeks have elapsed, I presume the men are made very aware of this risk. This was specifically noted in one of the studies below. 
But I find it hard to just accept things.
As a scientist I'm used to looking for the little bracketed or superscripted numbers or perhaps "(Scientist et al)", at the end of sentences. Then I can check out the information source for myself. So here, I thought I'd try and add those and pt it altogether in one place here - and you can do your own checking out if you feel the need.
Here are the research papers I've found for EBOV so far (there are also Marburg virus studies) - by all means send me any others I've missed and I'll add them.
- Bausch and colleagues  were able to isolate, in cell culture in the laboratory, infectious Ebola virus (EBOV) from the semen of 1 of 2 samples from a single recovering patient who had EVD.
- The sample was collected 40-days after disease onset; at 45-days he was no longer positive for EBOV
- No acute phase (active infections) samples were tested.
- 1 of 2 samples were also positive for EBOV RNA by RT-PCR (detecting a portion of the virus's RNA genome)
- Rodriguez and colleagues  could isolate infectious EBOV from seminal fluid 82 days after disease onset from a 27-year old male (also RT-PCR positive then). A sample at 51-days after onset was RT-PCR positive, but did not yield infectious virus.
- EBOV RNA , but not virus, in 3 other convalescent cases (33, 29 and 25-years of age) at times ranging from 57 to 101-days after disease onset.
- Rowe and colleagues , who examined the same patients, detected EBOV RNA by RT-PCR from 4 convalescent cases (27, 25, 29 and 33-years of age as above) at times ranging from 47 to 91-days after disease onset
- No infectious virus could be isolated and no viral antigens were found
- Emond and colleagues  were able to isolate infectious EBOV from seminal fluid collected 39 and 61 days after disease onset
- No EBOV was isolated 76, 92 or 110-days later