There is a third party, in fact he and Brian have an over 20 year relationship-Justin has one that lasts 10 years and ends when his lover dies of AIDS. But throughout the time that they are each in other relationships they continue to be "partners" and when Justin returns home the joins their relationship and for awhile there is also a woman involved in the relationship. They all have children together.

I would not suggest reading this unless you can handle Brian in a very loving an supportive relationship with someone other than Justin, although they do remain supportive and committed to one another.