No sex in two years. How do I get her to cuckold me?

Hello all.
I've read these forums for a few years, and now I'm finally a paying member. So here is my story, tell me what you would do. Input from women would be greatly appreciated. I appologize in advance for this long post, but I feel nobody would understand unless I go into some detail. Thanks for understanding.

I met my girlfriend in September of 2006. We were instantly in Love. A few months into our relationship, she told me about her last relationship and how her ex-boyfriend was a heartless jerk and before she could leave him she found herself unexpectedly pregnant. She didn't get any "signs" she was pregnant until she collapsed at work one day. She was six months along. 3 months later, she allowed a great family to adopt her baby. She had already moved out of her boyfriends and was living with her parents. Six months after we met, I got a job transfer to Northern California, and her living situation wasn't going well, so she quit her job and moved to this much smaller town than either of us were us to. I knew she liked sex a lot. So our plan was to make some money with a web cam. Two years later, that hasn't happened yet. When we moved in, I explained to her about how open minded sexually I am and how I would love to share her. I've told her a bit about me being bi, but two men grosses her out, although she has had many gay friends. She was a little unsure, but she started to pursue meeting other guys. She supposedly was had a date with a guy but chickened out. She doesn't like to talk about it, so I don't push the subject. I have my suspicions that he was a jerk screwed up her confidence because at this same time she was putting on weight. Her parents were complete jerks about the adoption, and bailed on her. They sold their house (just before the bubble burst) and moved back east to retire. Between no job, the homones from the baby, her parents bailing on her, and me always working at this new position, her petite little body got much bigger. I have nothing against bigger women, and have dated some big girls, but this girl doesn't look good with weight on her. Forward 2 years. She still has a weight issue. She comes close to getting the weight off her, but then has setbacks like hurting her leg or getting sick.....it always happens just as she is making real progress. Although she has quit smoking, so even though she gained all her weight back after quiting, she should be able to loose it faster because she is healthier. She is on the right track, right now. A few more months and she will fit back into her old jeans. We have not had sex now in over 2 years. She hasn't held out, but I've either been way too tired when I got home from work, or she says later, because she doesn't want to be seen naked, so she says wait until it's dark. Much of the lack of sex is because we have seperate bedrooms because I've developed a snoring problem. I have not cheated on her, and don't plan on it.......although I would love to get laid. I would love for her to cuckold me in some form. I would love for her to have a guy on the side, with a superior cock, but I still want to be able to have sex on a regular basis. One problem is that she thinks I have a large cock, and is very satisfied with me in bed, so she doesn't think she has a reamister to fuck anyone else. So, what I have been thinking lately is I will get her a little excited one night and bring up the subject. I would really like to explain to her that in a way she is already cuckolding me. Denial of sex, and we have seperate bedrooms. Now most of the posts I read on here suggest bringing up the subject of another guy during sex, and make sex when another guy is being fantasized about superior. That works for people having sex, but since we haven't had it in so long, I think I have a unique situation. So when I can get her a little loosened up from a take or two, I want to somehow suggest how hot it would be if we found her a guy to fuck her after two years intead of me. But not just any guy, I want her to have someone with a much larger cock. I want them to have sex enough that she gets stretched back out and will be loose if I fuck her. She doesn't own any toys, she isn't really into them, but I have been thinking that the night I bring up the subject, that I suggest we get her a dildo, and go online with her and have her pick out one of her choosing. She is more into girth then length, that why she is satisfied with my thick 5.5 inch dick. I don't think most of her boyfriends have been very hung, so she might not know what she is missing. I tried bringing the subject up about a year ago, but it got us into a fight. I think her weight is what really holds her back. She knows she gets treated differently/worse than when she was fit. I would love for her to have a black lover, but she has no interest in black men unfortunetly. I once accidentally left a cuckold/interracial website up, and she watched the videos and I think was horrified. Many of my girlfriends cheated/cuckolded me before I even knew what a cuckold was. Then later in life when I got over my jealousies and found out how hot it is to watch a white woman with a big black man, I convinced most of the women I dated to let me watch them. It was very easy to convince them. Why is it so difficult to convince the woman I love and want to marry? lol. So, I just want to know if anyone has been in a similar situation and/or what would you suggest in turning her into a slut. Thanks for taking the time to read this.