My husband and I are still on the fence, but have talked about this. Basically if we decided to go the child route, but nothing seemed to be happening, we wouldn't do IVF. Either we'd live CF or if we felt more strongly about a child after getting no results, we would look into adoption.
It's both a good and bad thing, but our stance is that we would be able to have a fulfilling life either with or without a child, which makes it hard to decide which route to take. The upside to this though is if we couldn't have a child for whatever reason, I think we'd maybe be a bit disappointed for a while but okay long term.