Think fiance has ADD- may cancel wedding

I'll try to make this brief but this site has been so helpful!  I met a wonderful man, 50 years old (I am 40), 1.5 years ago, we got engaged about 6 months ago and the wedding is in 8 weeks.  We are both divorced, have children.  He is a brilliant man, skipped grades in school, a surgeon with his own practise. 

I *suspect* he is ADD and I have been feeling overwhelmed about getting married.  I have been a working single mom for the last 5 years, very efficent, but very busy making ends meet.  (I had a short, horrible marriage to a narcissist.)  I really LOVE my fiance, more than anyone I have dated before and he is fun, caring, charming, romantic (or is this just the intense stage?). 

Things that make me think he is ADD:  he is always late, no concept of time at all or how long it takes him to do things, says he will do something then totally forgets ever saying it, his house is the worst mess I have ever, ever seen, even the outside is an eyesore and I thought it a red flag when a neighbour mowed a portion of the front of his lawn and fiance was irate saying him and the kids had planted some plants there that were starting to sprout (yeah, but who could tell in all that overgrown mess???), Christmas tree was taken down in April but now is still shoved in the fireplace inside, he is totally disorganized, had one staff quit mostly b/c she couldn't deal with him being late all the time and patients being upset, very slow at everything he does (I don't notice the jumping from topic to topic and even his driving is slow).  Although he makes a good wage he has had to pay his wife a significant amount of money over the years and is in significant debt but that doesn't stop him from wanting to go on trips, anything fun, etc.  I didn't know his financial situation until a few months ago.  I know he had trouble organizing and thought that I could work part time and spend time managing things at home.  Knowing the financial position he is in, we will still need to both work full time if we marry.  Fiance says we will both chip in, we will take turns cooking, grocery shopping, doing chores.  We are doing premarital counselling and in one of our sessions I said I was feeling that I would be overwhelmed b/c of having to work full time, look after my daughter, and have to do extra things with extra people living in the house.  Fiance was offended and said that it should be easier with us splitting things/chores and that he has managed just fine without me all the years so didn't know what I was talking about.  If you were to see his house, you would NOT think he was managing.  His 9 year old daughter will not have friends over to his house b/c of the mess.  Half his table and kitchen counter is covered in 3 ft by 4 feet wide of papers and the rest of the kitchen counter is cover in dirty dishes.  He was "supposed" to move into my place and rent his and this was supposed to happen by August 1st.  He is at work long days but didn't have his kids AT ALL for the last bit of June and all of July- so far HALF of the stack of paper on the kitchen table has been cleaned up and THAT IS IT.  I have already cleaned out my place, sold furniture to make room for his and painted some rooms in addition to what I normally need to get done in a day.  Fiance says he can move in in only a few days if needed b/c he can hire a company to pack up all his stuff (yeah, right, and all the junk comes here).  When I first met him he had started painting a room in his house; about a year later it was done but there was paint marks that he make all over the ceiling that he just left.  He is probably the least handy, worst painter I have ever seen. (I am not that great but a million times better at painting than him!) 

He "forgot" to pay someone we had do work here ($700) for 4 months after he got the bill, said it was b/c he didn't have the money but spend $3500 on a kayak in that time period  b/c he felt it was too good a deal to pass up.

We were planning a medium sized wedding, fiance was looking into honeymoons when I discovered he had no money and was wanting me to pay half of everything (he makes4X more than I do).  Even though we have zero money he still keeps sending me links to various vacation spots (we agreed to do immediate family only for the wedding though to keep costs down). 

We needed to do pre-maritial counselling worksheets and he lost his, I gave him another copy that he was going to do on the plane in June (we've had these sheets for 6 weeks!)- he still hasn't done them.    

Fiance has told me at least a dozen times that "he doesn't like to be told what to do".  I don't tell him what to do and I'm not usually a nag but OMG I can see myself being overwhelmed with having to do EVERYTHING.

Fiance also told me that "he cannot guarantee he will not have an affair when we are married".  We talked to our counsellor about that one b/c I was ready to end the rlsp but fiance said that in his heart he knew he never would, loves me dearly, but doesn't think that anyone can say they will never guarantee something b/c no one can 100% predict their behavior.

This man is an amazing lover, so romantic, but will really leave anything to have fun (go on trips, go to concerts, etc.).  I am quite responsible and like to get work/chores done first.

Fiance has never mentioned ADD and by his comments (things will be easier for both of us when married b/c we will be sharing chores, getting mad at the neighbour for mowing the lawn when his place is an eye sore) I don't think he has ANY CLUE as to what his reality is.  His mom thinks he is perfect and in her eyes, could do no wrong.  (To her he is a brilliant gentleman doctor.)  I need to be in court mid August with my ex husband and told fiance that I would rather have him and kids move in AFTER that b/c I would be stressed that week.  He was OFFENDED and said he felt like I felt that him and his kids would be a burden instead of being a joy to have there and he would be able to support me better that week by making all the meals.  (Actually, it WOULD be a burden to have them here then b/c I know nothing would get done- fiance would probably cook but everything would most likely be a mess.)

Fiance is divorced, blames his ex for a lot.  It does seem that she is a liar but with other things I can emphathize with her.  Fiance says she was high maintenance and complained she couldn't cope with 2 small children even though she had 2 cleaning ladies and someone to help with cooking- neither have family here, they got married after only 6 months of knowing each other and I am certain she must have been at her wit's end with his lack of motivation or ability to get ANYTHING done.  Ex wife has called fiance a wimp and not a man and after reading stuff on this site I think that she probably felt like a lot of you and that although he held a steady job and earned a good wage, he was unable to contribute in any other way.

Unlike some of the other stories on here, fiance does not smoke, drink to excess, take drugs, gamble, or watch porn.   He knows that I am scared about getting married this Sept, and gets very emotional and upset when the subject comes up.  He is extremely sensitive and then I feel terrible about hurting his feeling like that.

Do I make a run for it even though I deeply LOVE this man?  I love so many things about him that I have never found in a man before, his brillance, his love of reading, his ability to make me feel so good around him and feel so loved, beautiful, and special.  Do I even tell him what I suspect?  As a physician, I don't think he'll appreciate my insight somehow..... What do you think?