There is also the expanded situation B that can also be a little of C which is kind of the revers.. where you have the high quality single woman who has good qualities and often a good paying job.. (with or without kids of her own.. but often without).. meets the "damaged project" of a man who has kids that are a product of his prior relationship dysfunction/mental health issues.  The man may be a mooch or just completely ineffective as a partner/parent.. the woman usually has her own crap together.. and wants to be with this guy who she views as being a victim of circumstances.. (his EX/Exes)  because she claims things are "great when the skids aren't around".  I think this one is partially codependent where the woman gets the feeling of being needed and is easily lovebombed and forgiving of her partner's faults.. again.. because it ain't his fault.

I would also say that situation A could also include high quality males with kids who meet  high quality females with no kids.. and the guy is a good parent.. he prevents his partner from bearing too much of the brunt of a toxic ex if there is one.. and doesn't put his kids above his wife in priority.. but values his relationship with her as well. (kind of where my relationship is most of the time)  Not that there can't be problems with kids or the relationship.. but they can be worked through in a fairly healthy way. 

I don't think any relationship is perfect, and no person is perfect.. And I think it's not necessarily socioeconomic standing that determines whether people are good quality individuals and whether their relationships are healthy or not.  Type C isn't just "lower class" as in from a poorer upbringing.. but could include people with mental health issues.. substance abuse issues..moral compass issues etc..  

I think you will find it's probably a little more common that you will find the "good girl" who has a good job, lives her life right that falls for the "bad boy".. the excitement etc.. And as my dad often says.. if some women spent more time picking their partners than they do picking out their shoes.. a lot of heartach could be prevented.  I saw this with my bright and capable younger SD who had a string of loser boyfriends and I think it was almost like she went out with them.. just because they pursued her.. not because they were the right people for her.  She was in love with the thought of being coupled up.. and she was fine filling that spot with a warm body.. that loosely fit her version of what she thought she wanted.  Of course.. they all went down in flames.. and she was used by most every one of them.. financially and otherwise.. but you couldn't tell her that when she was in the relationship.  In steplife, it's not uncommon for women to somewhat develop a blind spot for the red flags that their potential partner is waving.. their parenting.. the toxic relationship they had with their EX (takes two to tango).. the kids with issues.  And then you have the women who are basically auditioning for wifeyhood with these guys.. playing nice with the kids and acting the way they think their possible partner wants them to be.. but then they get full on into it.. living with the dysfunction and then they demand change that their partner can't begin to give them.  And this can happen in B or C.  I think it's more of a female trait to do this..but I guess some guys play daddy to get the girl.

But, I would say.. yeah.. I'm mostly in A territory.  I have a very good job, no kids, well educated come from a good family (all families have their issues.. even what might be seen as high quality ones..haha).  Financially I have been able to ensure that we have survived hard financial setbacks from things like some serious illnesses my DH had.  But.. on his side, he was not a total disney dad and was really open to working with me on boundaries in our home.. and didn't subject me to his toxic EX as much as he could prevent it.  He expected his girls to be civil and behave.. and I never felt that I was not a priority to him..ever.  Yes.. kids are kids.. they get in trouble.. they can be disrespectful at times.. but they can also be interesting and it can be gratifying to watch them grow into capable adults. Both mine are indpendantly financially stable.. and have good to decent jobs and are fairly decent people.  They have both told me that I was part of what has allowed them to be so successful in life and they appreciated what I did for them.. especially my YSD.. who is very close to me.. but I have known her for almost 20 years at this point.. so most of her memory life!  OSD is a bit more of a "not my type of person".. but we don't have a bad relationship.. just not as close.

But, in situation C.. I think that there are both men and women who don't pay enough attention to the red flags at the beginning and allow things to move quickly to where they are up to their necks in a bad situation before  they realize it.  Of course.. there will always be users (men and women).. who look to ride on the coat tails of another person's success.  Obviously, if you know you are in C.. I would be making my exit plan.. that's no way to live!

I'm confused as to what exactly you're asking but will answer at the bottom of my word vomit.

You left off situations D, E, & FU. 

D = both solo parents meet, kids tolerate each other, bonds form and life is for the most part good w/ occasional speed bumps like any other home. 

E = solo parent W meets single man M and forms a deal where he moves them in because he wants a maid/love buddy and she needs a roof.  Not to be confused w/ E2

E2 = solo parent M meets single lady W and form a deal where he and his offspring move in, take over, destroy the place and suck the life out of her. 

and my favorite 

FU = no one is high class, no one is low class, all are humans trying their best and learning as they go even though one or both have kids. The issue isn't always easy when you then add in personal histories, ex-partners, ex-partners new partners. Those earn the FU since they tend to complicate life and ring it to hell quickly. No labels necessary. It's tough enough w/out labels.

Not every man is a loser w/ kids he refuses to parent, not every woman is a user who wants to destroy his bond with his kids, not every woman is a single mommy looking for a sugar daddy, not every man is a control freak. People are people, no two households are the same and I honestly feel 99% of us are really trying to fit our square hole families into a round opening and would be happy just to coexist.  Unfortunately most of us deal/t with a opposing parent of the skids who only causes more pain and anger. 

(my family is the FU catagory w/ FU going to the exes who threw nails in our road to happiness)

What ESMOD describes fits my situation. I was single, college educated, with a white collar career, financially stable, no kids, never been married, etc. I met a single dad who had a decent relationship with his ex and a terrific relationship with his kids.

I guess you could call him the "bad boy" type but only in appearance, really (tattoos, motorcycle, etc.) Aside from his appearance he is/was very committed, hardworking, loyal and family-oriented which is what attracted me to him - he is/was a far departure from the steady stream of fickle f*ckbois I used to attract. 

I moved in with him - but only because he lived super close to his ex and it made life easier for the kids. He is very domestically inclined (whereas I am not), but I do pay most of the bills - so I guess we play the opposite "stereotypical gender roles." 

Sometimes, when I'm wallowing in self-pity, I imagine a life where single financially stable me, met single financially stable man and fell in love and got married and now live a financially stable life together. One that involves vacations, and summer homes and luxuries that I don't have to buy for myself. 

But I recall it being just SO HARD to find someone that fit the bill when I was single. I don't know why! And now that I'm pregnant, my DH's ex decided to become high conflict. *shrugs*

So now I'm part of this whole whirlwind of a mess and I do love my DH and anticipate staying with him forever but IF it does end, then I'll be the one with baggage who may attract someone without.

It's like a weird version of the movie "It Follows" except instead of a demonic haunting transmitted via sex it's a demonic haunting transmitted via vows. 

Thai is pretty sexist and racist TBH. Not everyone falls into a stereotype. 

I think figuring out why other people do what they do is waste of time. It's more important to figure why you do what you do.

If you think you are in a situation C, you took unstable low class woman with wild kids to live with you for free. And she isn't even nice. hhmm

So why do you think you don't deserve high class stable women who would be equal contributors financially and otherwise? Why do you settle for this horrid arrangements? Why "take anyone in"? Why not look for equal partnerships? This is 2022. Why have this mentality of taking people in? Focus on figuring that out. 

Therapy could help. Is she the first woman of this kind you entangle yourself with? Look into it. And start working on eviction notice. I personally wouldn't let free loaders live with me. Why are you ok with this? 
 

You realize you made a mistake in moving a "lower class" female with unruly kids into your home nearly expense free while you're on the road and you're upset it's not paying off for you like you thought it would.

Perhaps higher class women don't want to date a person who is on the road so much. I don't know.

But it works both ways that when you lower your standards to get some of your needs met, there is a cost. In this case, you have allowed this situation to decline to a point where you've got a lot of resentment.

If you don't love this woman, don't stoop to her level and use her while you're on the road - like she's using you. Have some class and cut her loose to find someone else to mooch from.

I don't think it will go over well if once you're off the road, you tell a new person you're dating, "Yeah. I was in a long term living-in arrangement with a woman who used me. But I kept her around because I was on the road and it worked for me. But I just cut her loose so I can find a better quality woman." ICK

It would show more maturity if you were willing to be on your own instead of being used and using someone else in return.