Have you ever been part of a blended family? 

I recommend that you watch the move A.C.O.D.  It is all about the scenerio you are researching and writing about.  It is billed as a comedy.  I found it more a tragedy of parental idiocy.

I have not experienced what you are planning on writing about.

Your intended publication certainly can hlep many people.

Good luck.

I actually dated a guy that went back to BM. We were together 8-9 months. He had met my kids but didn't want me to meet his. I was driving to work one day and he drove right past me coming from BM's direction (she lived in the same neighborhood as my sister). He told me he was at his house the night before and wasn't feeling well. I called him and told him I had seen him, he said they reconnected for the kids. 

We broke up, they got back together. Well, the other way around but semantics. It was for the best though, because less than 6 months later DH and I started dating.

IMHO the key elements of this scenario are the manipulation, tragedy, and pain of the new partner.  Too bad there isn't a lab test for Xs with prior relationship children that can label them (with a prominent forehead tattoo) as manipulative, characterless, wimpy, cowardly, spawn worshipping, codependent waists of relationship effort.

Be happy to share a few stories but where is the contract first.

I dated a guy for a year. We lived 2 blocks from each other and BM lived a mile away. She invited me over for birthdays, called me for favors with the kids. My kids & his kids were ages 8, 7, 6 & 4. He also helped out with my kids. Then BM stopped asking me to babysit so much and hired a sitter. The sitter told me years later that my BF & BM were in counseling and thats why she was babysiting but yet she'd see him & I out on the weekends & it made her sickthis was in 2001. Last i heard they are still together

Thenewrere I'm sorry that you've been snapped at by some of the more abrasive members of this site. This site actually used to be ten times worse. It got so bad that I stayed away for a couple of years. When I returned I noticed that administration had put some steps in place, to try and ban behaviour that is regarded as abuse. 

Anyway, I personally haven't had my DH go back to BM. But I did read about it once on the website "The British Second Wives Club". In this case, the guy reluctantly went back to his ex, largely because of the kids sake. Then after several weeks/a few months, he realised he'd made a mistake. He rang his jilted girlfriend and said that he wanted to spend the rest of his life with her. 

The British Second Wives Club was a site full of really nice people. Maybe hang around and see if they'll help you.