To see that scene with Margo and Ryan you don't need a save, just go back to the scene before D goes to the park , click on her head (top-right of screen) and set there the MMF route with Martin to NO. Then play the game from there and when you have to chose between Olivia and Margo in the park (if you have the 3some routes with both of them on yes), chose Margo. That's what i did and what I always do whenever i see in the WT that i may lose a scene that I want to see if something there is set to yes or to no.
Fortunately those settings can be changed any time.. probably also whenever the time will come for D to finally get a BBC in her pussy (if we are still alive). We will just have to set there the MMF with Martin to yes again. Or we can always wait for Lain's mod to be updated to the last version..
It's indeed a big shit that we have to chose there either 1 or the other instead of having both (and even between Margo and Olivia we must chose). But since it seems a swinger scene with Graham/Olivia won't come till the end of the year, if at all, and any kind of sex scene with Martin will only come in some .. 5 or 50 years from now, if at all, the only thing the pervs of us can do is chose to see that scene with Margo and Ryan for the moment and get this way just another man's hand on D's naked boobs.. What a great progress on the corrupted D route lol! But, OK, better than nothing.. At least the discussions before and after that scene do set some future trends and clarify some things..
From what I can see, it appears that MrDots got scared by the many players who threaten to leave if the game doesn't remain vanilla and has probably decided to go on that way till the end of Ch3, plus setting up some mini-harem & polyamory routes with Dee + other girls (which indeed are necessary and nice). As for sharing Dee with other men, I can only hope that at least in Ch4 us pervs can finally see her going ballistic and fucking every man that's not hiding in a tree till you count to 3. In this chapter that just won't happen! She just goes on acting BI-sexual, which gives MC even more girls to fuck..