I'm not sure I can offer any advice, but my W and I went through IVF, and it's failure was the straw that broke the back of our strained relationship. We went to several adoption clinics, but as I turned to internet porn she turned to EAs. I guess we both couldn't face the pain.
The IVF doctor basicly slammed the door in our face, I guess we ruined his success rate. They should've recommended/provided some counseling, something. It was devastating.
If W and I get back together, we may resume the adoption process, assuming we're not too old. As if there weren't enough stress, it's like we both have another biological clock ticking (generally 45 is the upper limit).
You need to be sure you're bringing the child into a committed R; bringing it in and divorcing could make things harder over all, I'd think. Certainly, the EA's must be ended.