Can Effexor Worsen Erectile Dysfunction?

I am coming off paxil. currently taking paxil (20)g 1x a day) as well as wellbutrin ( 300mg) 1x a day). I will start with 1/2 a pill of paxil for 2 weeks while continually to take wellbutrin. The 2nd two weeks I will be taking 1 pill of Effexor (75mg 1x a day) while still taking the wellbutrin. This is what the doctor has planned for me. What can I expect, as far as changes in my persona , etc. I have had a problem with E.D before taking this type of medication and wonder if this medicine will be any worse as far as E.D goes. Also what would be the best E.D medicine for me to take along with this med.