I have had the same problem. I have arched, open doorways between my foyer and the living room and dining room. At one time, I did paint the inside of the arches the same as the foyer color, but it never really looked right. I ended up painting them white, like the trim color. If you look at the photo I just posted in my own query "WWYD with my LR windows?" you can actually see one of the arches in my photo, if you're interested.

LOL... if you continue reading in my post about the windows, you'll see that not everyone agrees with painting the archway white! I just saw that after I posted here.

sueb20, I wonder if it's because the doorway on the other side has brown moulding. I have no moulding anywhere in any doorways.

I thought it looked fine to me.

I just can't paint the inside of mine gray, and then see it from the other room, nor can I paint the living room color on it and see it from the family room side. I did something like this between the kitchen and dining room years ago, and I think it worked out fine.

Guess I'll go for it.

I painted the inside of my archways white like the ceiling color. After all the inside of the arch is like a ceiling when you are under it. That's my theory. BTW all the trim in my house is wood so it was not because I was trying to match the trim.

If you don't like them touching, I can't quite see how the colors work well together, how the sight lines work, etc. Because they kind of visually "touch" when you're standing in certain places. (Did that make any sense?)

I think that if the colors work like you say, from room to room, then theoretically they should butt up against each other just fine. Right now, you are looking at this under the proverbial magnifying glass. Perhaps you can paint the arches one of the room colors and the "touching issue" will fade over time.