The point you made about not having a positive marriage to serve as a role model for your W is interesting to me.
My H's parents (and they are both very nice people and treated me like a daughter the moment I became involved with H) have a very sad marriage. They both sort of live their own lives, have zero respect for one another and it really is a marriage of convenience. They both have openly said it is up to the other to "fix" it and both have stood their ground that it is up to the other one. They don't fight/argue, there is no physical abuse they just sort of drift along and just so happen to live in the same house. From the outside they seem to have it "all". The beautiful house in the upscale neighborhood, two thriving careers, the vacation home in Florida, the membership to the fancy golf club, the two wonderful vacations they take each year, no debt and blah blah blah. But those are just "things". Little do most people know when they take those fabulous vacations all they really do is share a plane ride, hotel and maybe a meal or two. The rest of the time is spent as individuals.
One of the saddest things I ever witnessed (and to my in-laws they never batted an eye which IMO is even sadder) is a conversation they had in front of H and I. To them it was just a casual conversation and they said neither of them were interested in hearing about each other's day when they got home at night and really wanted no involvement in each others lives. They said it so casually like they were talking about what to have for dinner but my H and I stood there stunned. They even sort of laughed about it as if this was a normal way to conduct a R.
My H has said for YEARS he never wanted a marriage like his parents yet he operates just as they do in every sense of the word. He does not feel like he should have to work in a marriage and it is up to the other to mind read, fix things and do all the work. As long as my H brought home a paycheck and brought me flowers each week then he was doing his "job" as a husband. To him it's a "feeling" and once its gone, its gone. Funny thing is the R my H is in now (his affair that has lasted for close to 2 years) is getting "real" and the "fun, sex, fantasy" is dwindling and real life is setting in. My guess is once the work starts he will shut down emotionally until he can't tolerate it anymore and find a new "fun, sexy, fantasy R".