Our plan is to have the share/swing path be the main path. The other paths will, for the most part, be avoidable side routes.
There will be setup scenes for these paths, such as the blackmail path, but there will be decisions involved in these that will allow you to 'end' the path before things progress too far. Those decisions may not be in the form of a Yes or No choice to continue the path, but choices you have made will impact how the path progresses.
We are planning on having cuckold, cheating, hotwife paths as well as all forms of NTR (netorare, netori, netorase), but these will be avoidable as well, again after some setup of the paths where necessary.
For the swinging/sharing. We plan to have choices for which couples you swing with. These may not always have a 'good' choice, but there will be a 'lesser of two evils' choice at the very least. For instance, there may be two couples you can choose from. One would have a 'bad' husband, but a 'good' wife, and the other being the opposite with a 'bad' wife and a 'good' husband. We could have a totally 'good' couple and a totally 'bad' couple to choose from as well. Those choices that you make on which couple you go with will also have an impact on how your wife reacts in the future as well.
We are trying to give choices that allow you to avoid the parts you are not interested in, or the people you are not interested in, however, that is not always possible in order to advance the story. So there could be some scenes that will happen without a choice for them. Again, like the setup of the blackmail route, where we have to build up to a certain point in order to keep it as real as possible, while still moving along in the story.
Hope that answers your questions, but feel free to ask more, and I will answer to the best of my ability, without giving away too much.