FlyingPhoenix

K1 is generally quicker, but as the others have said there's the extra stuff to do when you get to the USA with adjustment of status your 2 year conditional greencard before you are a completely permanent resident. Me and my fiancé have done the fiancé visa and we got approved last week so it took us 3.5 months total and I will be back with him in a few days. There is also the pregnancy which could work in your favour perhaps it will speed up the process if you include a few details about it in your petition so you can get back in time to have your baby in America if that was your plan anyway. So yeah if you want speed then I'd go for k1 and just work through the extra stuff that you have to do when you get to America for your residency, it's mostly paperwork anyway and at least you will be with your husband through it all.

Okay so the fact you had a return flight for your wife's visit is definitely a point in your favour because although they may be suspicious it's still evidence she was planning to return. I think calling the NVC is a good idea and hopefully they can give you good news. But incase it isn't what you want to hear you are legally allowed to stay 90 days maximum on VWP so perhaps you could extent her visit then she can return to the UK for a week or so to do the interview finish everything off then come back on the visa. There should be a date where they stamped her passport when she entered on the VWP and that's the date the 90 days is up and she would have to return to the UK unless you have something sorted out. Hope that helps

K1 is generally quicker, but as the others have said there's the extra stuff to do when you get to the USA with adjustment of status your 2 year conditional greencard before you are a completely permanent resident. Me and my fiancé have done the fiancé visa and we got approved last week so it took us 3.5 months total and I will be back with him in a few days. There is also the pregnancy which could work in your favour perhaps it will speed up the process if you include a few details about it in your petition so you can get back in time to have your baby in America if that was your plan anyway. So yeah if you want speed then I'd go for k1 and just work through the extra stuff that you have to do when you get to America for your residency, it's mostly paperwork anyway and at least you will be with your husband through it all.

Hello
I just went through this. Cal the NVC 603 334 0700 have all the info ready to verify who you are and they can tell you when the interview is scheduled and when the letter was put in the mail. It will be cheaper to have the USC make the call. If you have the info ready and are cordial you should have not problems. We were told the letter was put in the mail on the 29th of May and my lady got it on the 31st. No use in calling London. You can use the e-mail form but it takes about a week to receive an answer.

It's tough say really what USCIS will think of your situation, I think you said you have already filed for your boyfriend and you explained here you have been together a while already so that's understandable, I would just say you have to be prepared for scrutiny, because you filed so soon after getting your divorce and they might be suspicious of your relationship from the start.
There is also the issue of you marrying an illegal immigrant, that and you having an affair are probably things that may look suspicious or immigration may not look kindly on.
The age isn't usually an issue, me and my fiancé have a 13 year age gap, him being older than me and all we have left is our interview.
As I said it's really hard to determine whether your circumstances will be a problem because although they are tough with immigration, if enough evidence is provided that you have a genuine relationship then you might be okay. If you hadn't already filed, I would have recommended using a lawyer because they can be a real help with your kinds of cases.