Hi Pas
well the situation is slightly different but prehaps you can take some perspective from it!!
a friend of mine shares a house with a family and they have another lodger as well as having students for short periods on exchange!!
now of course it is a large place and they share, but the family have 2 kids (sorry not sure how old, but still well below teenager from memory!! think grundschule age)
he is really happy, has been there for 3 years now or so, the other lodger has also been there for over 2 years. so it is more like a w.g. but with a family!!
from what i understand is they cook seperately from the family (due to work times, friend is a shift worker) but also together if they are there at the same time. we have had a party at the place for his past 2 birthdays and the family were not to be seen (i think the kids were also staying away for the night!) course they don´t accept such parties on a regular basis!! i know the 2 lodgers (friend included) help out with
babysitting (i guess you probably wouldn´t have this as a huge issue due to the access you have to your kids, maybe only on the odd occasion during the holiday periods?) but they have use all facilities, watch t.v with the family, or by themselves in the lounge if the family have gone to bed. they don´t feel uncomfortable!! course i can honestly say my friend is one of the most nicest, unfussy, flexiable persons you could meet. but he also goes out partying and returns in the wee hours sometimes but this doesn´t bother the family (as he doesn´t cause a ruckus when getting home of course, out of respect to them!)
the only question is can you afford to trial it for say 6 months or so? (wife agreeing of course) i think if you set some ground rules, make sure the person knows they are on a trail basis, but to expect them to share half the rent maybe a tad harsh. i mean if it included all extra costs, but maybe a slightly lesser rent but half the bills etc. (i can´t tell you what the split costs are in my friend situation unfortunately!!)
opps, just re-read your post, and you said half including costs. that is reasonable!!
point being that if you are flexiable and reasonable, it is just a matter of finding the right person and it can work!! (not all have had the same experiences as playtime!!)
at the end of the day, you want to be close to your children and in oder to do that, anything is worth considering!!
best of luck, and i hope you can stay nearby whatever you choose!!