AmyWrites

IMHO, consider calling off the engagement and not marrying him. Your post is filled with scenarios that you believe will make you unhappy. You mention your fiance a couple of times and associated with the expectation of a bad experience. It seems obvious he won't change his lifestyle for you and expects you to make all the concessions. IMHO this is a recipe for a very unhappy marriage.
I don't mean to be insensitive or cruel and I apologize if that's how I sound, but it seems there is nothing in this relationship for you. Pragmatically, people need far more than love to make a happy union.
Good luck whatever your decision.

There is no limbo here, you just need to accept the reality that returning home seems to be your only option.

There is no limbo here, you just need to accept the reality that returning home seems to be your only option.

There is no limbo here, you just need to accept the reality that returning home seems to be your only option.

There is no limbo here, you just need to accept the reality that returning home seems to be your only option.

One more thing OP: no offense, but you also seem very close minded and rude...just as you said people are in your country...I guess the apple does not fall from its tree, does it?

While I understand the OP's wish to stay here, she has to draw the line and start to provide a stable life to her kids. Seems, she is financially broken at this point, she would be way better off in Europe, either back in Spain, or elsewhere. I have friends who came to US for a couple years on an F1, they told me the bad side of Spain, but also the good side. Sounds to me that, even if Spain is 100 years behind, considering the former Soviet Union countries that are 250 years behind, Spain is still a good country. Anyway, not saying OP must return to Spain, can choose any other countries in Europe, but instead of so deeply focusing on fighting with tooth and nails to stay in the US realize this is not a feasible option anymore. She has to be a bit more realistic than that. Anyway, wish her the best with whatever she decides.

Exactly. And about being a "citizen of the world"--so just tell CBP you are a citizen of the world and they will let you in because you then suddenly have the right to enter? (As OP said, she has the right to live in this country...)

You say you are looking for advice. I've seen plenty of posts on this thread giving you the facts as it is and advice with that. However, it wasn't the advice you were hoping for (aka no one mentioned the imaginary XYZ visa you can apply for to stay here), so you disregarded all the advice and made it off as people being rude. All I can say is good luck with your journey.

This kind of post really rubs people the wrong way because we all are working/have worked so hard to be with our loved ones. What you're going to attempt is clear cut immigration fraud. Your actions are the reason legal immigration is harder for the rest of us.
Judging or not, that's why you're getting attacked on here. So if I were you, I'd talk about it with your husband and your kids and leave Visa Journey out of this.

I wonder if a sham is in process?

I'm sorry, but this all sounds too convenient. You came here by marrying a USC, you want to divorce after getting your GC, remarry your first husband and then petition for him to come here, it sounds much like immigration fraud.
It doesn't matter that the marriage to your first husband was legit. They will look at why you married him the second time. Even if you genuinely got back together, you will still be heavily scrutinized.
Now, I'm not accusing you of fraud, but that is what it sounds like and that is what USCIS and the CO will see. I don't know you and I don't know your situation, but here is what would happen:
If you do decide to divorce your current husband because you want to marry your ex, you will have to prove with a very great deal of evidence, facts, and I don't know what else, that:
One: You didn't divorce your ex to marry a USC. (Sham divorces are also a very big deal for USCIS)
Two: That you didn't marry your current husband for immigration purposes.
Three: That you didn't marry your ex again for immigration purposes.
There are people that are married, divorce, marry other people, divorce, then marry their ex's. But when immigration is involved, the suspicion of fraud is going to be very very high.
If your plan is to get married for the purposes of bringing your children's dad and not because you genuinely want to get back with him, then don't, just don't. Let one of them petition for him when they are 21 and is a USC.
If you and your current husband aren't working out, then that is another story and something that the two of you would have to deal with.

Expect problems, because on the surface it looks like you married an American in order to evade immigration law and facilitate your children's father's entrance into the US.
Does your current husband know you are planning to divorce him? In order to naturalise under the three year rule you must be living together with your US citizen spouse in a true marital union.

Slim to none, and no citizenship.

Ha. Ha.
Tell your wife to go ahead and call US immigration.
She can not withdraw her sponsorship even if you divorce.
Tell her if she tries to f... you over, you will get means tested benefits that she will legally have to reimburse the government for because of the binding I-864.
In fact, you can get 125% of the poverty level from her based on the I-864 as support after the divorce.

Can we NOT encourage people to use VAWA unless there's abuse involved? Jfc

Ok, this is really sad, but your wife left today to take care of her mother who is ill and your first concern is about what to do if you decide to end your marriage?!

It seems to me that this is an abusive situation, where someone brings in a person and her kid and then refuses to do what is required so that person can have a normal life in the US. I wouldn't be encouraging it, myself.

^ not correct at all
First only a US citizen can petition for their mother. If you are a citizen you begin by following the guides at the top and filing the I-130 and assorted other documents. Processing by USCIS takes about 5 months. The it goes to NVC where you provide the affidavit of support. Then it goes to the embassy for an interview to be scheduled. A parent is considered an immediate relative so there is no wait for a visa number. Current processing time from filing to receipt of visa is about 12-18 months.

Don't even think about a proxy marriage. As I said earlier it won't work and it will can you for any chance at a K-1 visa also.

Marriage by proxy is NOT valid for immigration purposes unless the people meet in person afterward.

You cant.
How do you know you want to marry this person if you've never met them.

I'm sorry, but you cannot use two US citizens' marriage after 10 years as an example to justify your completely different situation, especially since your foreign wife has violated a ban.
I would recommend a lawyer.

It's really just in the wording. Consular/embassies do not "Deny" anything. We always say that. They "Refuse" to issue you a Visa. Only USCIS can Deny. If that is the wording they are getting ready to send your petition off to USCIS where as stated it will expire if it hasn't already in 2 days as you say.
AP is what it says "Administrative Processing" They are finishing up their report to add on to your petition.
Since they think you are family. I would imagine what cousins sister- brother you need to be sure to have DNA/Bloodtest test something to refute so when or if you reapply you have evidence. Getting married will not fix a "we think you are related". Did they actually say that or is that something you think. What did they say at interview?
Most definitely get a lawyer.

See above