Thank you for bringing your question to Just Answer!
I think you might do well to wait until he has had more sessions. If you allow him back into your life so soon, he may feel like he can drop out of therapy and still keep you. You have set an appropriate boundary, and it's important to keep it.
In the meantime, start educating yourself about sexual addiction. Dr. Patrick Carnes is the most well-known specialist in this field, and he has written several wonderful books that will explain sex addiction and also give you information about how to live with a sex addict (or decide not to) Here's a link to a list of his books: http://www.amazon.com/s/ref=nb_sb_ss_i_1_11?url=search-alias%3Dstripbooks&field-keywords=patrick+carnes&sprefix=patrick+car
(For some reason, I couldn't access Amazon's Australia site, hopefully you will be able to search for his books there).
If after reading about this condition, you believe that he does have an addiction, one other very important resource available is S-anon, for the partners of sex addicts. http://www.sanon.org/MeetingsAustralia.htm If you decide to continue this relationship, you'll need a lot of support, and S-anon is a great resource.