Dear OP,
Was up til 3am reading your awful surreal time. It brought back some memories.
It will be five years in January that my Dcs D left (although the affair had been since I was pregnant with DD - I discovered it - he still denies it to this day - other than once during family mediation - and his PR amongst family and friends is that they met the day after he left and boom!). I wanted to see what I can say that might help now or as things move on.
It is still very very early days for you. Many posters have wisely said don't feel pushed into anything being set in stone until you are ready to have absorbed and digested it. I second that hugely!
My biggest tip, now, is to search for comments by a very astute Mumsnetter known as WWIFN. She has some very pertinent tips about how to make a sense of life post an affair. There is also a very good book I have read and has been often recommended called Not Just Friends by Dr Shirley Glass. Your H has given you some explanations re why he did what he did but there is some very helpful information about how people give themselves "permission" to have affairs and how most affairs are not due to a bad marriage or lack within it. (as that too hurts like bry that some assume no smoke without fire) It doesn't set out from all-people-who-have-affairs-are b*ds either (but in your case....)
Anyway - I'll try to be helpfully focussed (brevity isn't on my CV) as I think I can.
- PRACTICAL.I'll start with what you have mentioned re DIY and your D coming round to do it.
You've mentioned you don't recognise the person doing this (your H and his personality since affair was discovered) and you are right to bear that in mind with all financial stuff going forward.
My solicitor of 20 years practicing family law says the feelings always harden VERY quickly regarding money even with small dcs in the mix. So... Whilst I don't want you to cut your nose off to spite your face (ie have taps dripping or stuff not working) don't do any MAJOR work until the house financial position is sorted that might increase its value. (or keep a record of all expenditure so it is separated out in any valuation to come).
If he is nice/remains so about ££ - a pleasant bonus. Expect/assume less behaviour wise though, and smile and keep your cool through any self-serving bluster when you don't let him get his way (not out of spite though, obviously).
If you haven't already - ask for his keys/change the locks (you accidently lost your keys so had to...) so YOU are in charge of access to your house. (Mine came round after 2 years!! and took down the Tom Dixon lamp shades whilst I was on holiday with Dcs, as well as riffled through all the drawers boxes in the house. His stuff had been boxed some time back)
- EMOTIONAL. Most people are considered "serially monogamous" so if they wish to change partner they have to find fault with the current one to create distance. PLEASE keep this in mind always when/if you get any verbal that does you down.
Also - the most amazing woman who has walked the planet (OW!) for whom you should be grateful your Dts get to breathe air with! AGAIN - he needs to pedestal her to justify what he has done. Only this super human makes it ok to have been such a Weapons Grade w**er. IT ISN'T TRUE and most likely he knows it too.
Also - to me, the whole being-such-good-friends-with-Ex-and-his-gf was green lighting/goading his leaving you by her (you may well end up being perfectly civil for your Dts as I am with mine and his) but it reads like a huge nudge to encourage him to do it and showing no bad repercussions so OK. Was her separation along similar lines? He can earn that if his behaviour is reasonable and as time allows! Don't feel railroaded or bad because it's so blinkin raw ffs still!
- FRIENDS
I found mumsnet invaluable. It sounds like you have a good friend and a Db too. Sometimes in RL I found people v judgemental and made me feel worse re decisions/missing him and can be v sanctimonious. Unless they have experience then take what they say with a pinch of salt. I think there is better advice here, sometimes.
I, too, found it hard that I seemed swapped out of mutual friend gatherings etc. quite quickly. And there didn't seem to be anyone who called either of them on up their behaviour (esp as he is life and soul!) I am glad some work people have shown you what they actually think even if they don't say anything to him. A hard one that but assume there's more that think it.
- DCS
I did find it useful to talk tomany of my peers had divorced/separated parents (and was saddened tbh how many had been). Listening to what worked/didn't work from their perspective helped. Unanimously was don't bad mouth the missing parent. All children who heard it only felt the parent saying it was mean. Most - all - worked out who had them at the heart of their decisions. (A bit of a wait but...) And none fell for bells-and-whistles presents in lieu of the calpol giving parent at 4am!
- MEDIATION
Again, invaluable. Family mediation rather than marriage/counselling. It makes sure he can't keep thinking with his c*ck and the children are the forefront of all decisions. You can thrash out some issues re when is OK to meet OW (given he felt no need to tell them, or you, of his wonderful new gf whilst the affair was under wraps then a few more months more is fine ... until you are satisfied that her BJ technique doesn't lose its novelty and they are actually a couple with some staying power - there is no need AT ALL for her to meet your children.) I think it is very important for you if you can, and a lot of the puff and bluster holds no sway when faced with a professional third person!! I think courts hold a dim view going forward if you divorce - if it hasnt been done. You can satisfy yourself that he has thought where booze/sharp knives etc etc are via this too etc etc. Also a shared parenting between you two (not OW version of parenting - which may be fine but isn't her beeswax - eg re bedtimes, discipline etc)
Sorry OP - turned into a stream of conciousness after all. Can't edit as need to take DD to build-a-bear shop!! I hope it helps. Heartfelt love girl! You sound a very sound woman!