In my perspective, I see the relationship between Lena and Ian is somewhat different but still it has so much to offer us in the story. Specially from Lena's point of view, her ideas about her modeling career and flexibility that she has about others seeing her naked body at her work, give strong signals that Ian needs to have good understanding about Lena's profession and specially about the fact that it's her profession to get naked in front of her coworkers and other involved people. This will really work with the Billy's involvement in the modeling industry. When Lena decided to accept the Billy's offer, it opens a chance for Billy to shape Lena's career path in the future. Obviously, Billy's intention might not end up in modeling industry but smoothly step into porn industry as well. But at the initial stage he might do some solo shoots with Lena and other models (May be with Cindy also) and eventually shoot some artistic nudes with the involvement of male talents. (Mainly with Jeremy, the bouncer and Billy himself or some new Afro males with similar vibe of Tyrone's friends from GGB)
This might be a big deal for Ian because of his personal thoughts are not into sharing stuff. (When Jeremy ask Ian to show Lena's nude images at peoplegram unlike Jeremy, he just refused to do it.) but in Lena's perspective "it's just professional work and she's just doing her job and she has nothing to hide from Ian" At the beginning, the shoots happen without any porno sexual interaction but eventually things should get sexier and more intense. Billy should play a major role in here and he should clear the doubts of both Lena and Ian with very professional approach. Billy's artistic / modeling ideas should be developed into more sexual and intense level and eventually Billy should ask Lena to participate artistic soft-core content which demands sexual touches between Lena and her male coworkers. (Holding penis, Guy touching Lena's private parts kind of stuff should be involved at this level). At this point, Lena should have clear separation in between her modeling career and love life. Things that she does at her work has nothing to do with her love life, because she has everything that she need, in her current relationship with Ian.
At this point Ian should also have to have moderately clear understanding about Lena's thoughts and her honesty about their relationship. There might be friends of Ian, who directly questioning Ian about Lena's career and stuff. (specially someone like Perry) Even though he also has some debuts about the limits of her profession, Ian should defend Lena at those situations. At this moment Billy and his team should set up the ideal moment for Artistic shoot with "Real sexual interactions" in their list of work. At that moment Lena may also have some doubts about "how would this impact her relationship with Ian" but eventually it should fades out when she realizes she only has feelings for Ian, and nothing can distract her bond with him. She must explain this to Ian and convince him in favor of this decision. Ian may have lots of debuts about this and might need immediate explanation from Lena about this whole professional work. (This discussion should happen before the shoot and if Ian interested, he should be able to see how things are happening in the set)
With that Lena should explain Ian about all her inner thoughts and how she feels about love between them and should make a strong and clear impression on Ian's mind about her thoughts about their relationship and her modeling career. As an example, if she has to have sexual interaction with one of the Afro male talents at the shoot, she is not doing that because she needs to have BBC or any other lust that she is missing in her relationship with Ian. She is just doing her job and when she is on it, she will do it as a part of her professional work and nothing more about that. There is no romance, no sexual lust or feeling of guilt in her mind. After she finished her work, she goes back to Ian and all the love and romance happen in there...!!!
If some creepy dude try to approach Lena and try to have some casual sex with her, it just not going to happen because she is not a slut that cheat on her guy. This also apply for her coworkers too and it also not going to happen (Even though they are having sex on sets). For Lena sex is not something happen casually, it is something that you do with your romantic partner, (at this point with Ian) and except that she will do it under her professional work with the per-defined set of rules in very professional manner.
For the other people that outside of modeling industry, Lena might be a slut, a prostitute that sell her body, or a cheating maniac that do anything whatever her profession demands. But in her perspective, she is doing her job and she has nothing to do with other people's thoughts on it. She is not cheating at all, but she knows she can’t change other people’s minds about it. And that’s why she finds Ian as a special person that try to understand her life with his unconditional love and affection. And that’s why their bond is so strong.
After all these dramas, things should not just end at Ian’s and Lena’s wedding just like in GGB, the story should move forward after they even got married. Yes, there should be a decision whether Lena continuous her work in porn/erotic art industry. Whether Ian and Lena decided to have a baby? When Lana is pregnant with their baby whether she decided to continue her work in porn. And what will be Ian’s thoughts about all these things happen in their lives. We must understand that Ian is okay with Lena doing porn not because he has cuckold thoughts, or he is enjoy watching other men having sex with his wife/girlfriend. He accepts that as a part of Lena’s life, and he will support Lena until she decided to end her career and so on.
How this going to affect Ian’s relationship with other people. How does his parents, friends and coworkers going to judge him with all these things that happen at Lena’s professional life as Lena and Ian define it? And how Lena going to defend herself in front of her parents specially with her father? Will Molly and her husband Ed will support Lena at this point also or will they have different thoughts about it? From Ian’s and Lena’s perspectives this has nothing to do with slut shaming Lena or Cuckolding Ian, it’s all about how things happen between two of them and the way they accept it.