Given a travel related situation, and given a specific question about the situation, summarize the question into a title

Example input: The green carriage is of course first class. This would be our first preference with our 5 month old baby in lap, because of the presumably larger toilets for changing and whatnot.  However, the baby being a Western white baby... will occasionally babble, screech or cry uncontrollably for a little while.

Speaking in terms of Japanese culture, should we avoid Green class tickets if we are taking aboard a potentially disruptive baby?

Example output: Japanese train etiquette: Is it acceptable to take a baby in the Shinkansen Green Car?
Example explanation: A person gives a detailed description about a situation where they would prefer to travel on the Shinkansen Green Car but is doubtful if doing that would be against the Japanese train etiquette since they will be traveling with a baby. The question is summarized as Japanese train etiquette: Is it acceptable to take a baby in the Shinkansen Green Car? for easy indexing the next time someone searches for a similar phrase
Q: How soon can I return to the US from the UK on an ESTA after abandoning the K1 visa

Background

My finacee and I were going to marry in the US as she was doing a PHD there (she is American). However whilst I was over there on my K1 visa, she decided to transfer her PHD to the UK. So we didn't go ahead with a wedding there.
I returned to the UK after spending the maximum 90 days there. Now I would like to return on an ESTA for a month or so. Ideally, I want to go back right away, I know much of the decision will be made at the border, but I can explain the situation well enough and i'm not concerned with the border officer not believing me as I have the expired K1 with me. I'm just wondering if I may have missed anything obvious? And if I get denied at the border, what impact it will have on future ESTA travel.

A:
How soon can I return to the US from the UK on an ESTA after abandoning the K1 visa?