One indoor one outdoor cat-problems?

[jenny]

Hi,
I already have one outdoor moggie cat (non pedigree 18months), he is gorgeous natured and very streetwise. He is quite independant, and comes and goes as he pleases.
I have been searching for a maine coon for months and finally have one ready in a few weeks. however i know the breeder and many others believe the maine coon should not be allowed out.
may seem silly but do you think it will be cruel for the maine coon to see the other cat coming and going? i plan to build an outdoor play area for the maine coon so he still gets air.
i just want my new kitty to be happy and not feel like he is not living life as much as my other cat.
can anyone with similar experience or indoor maine coons give me advice on what is best for the cat (sometimes i feel it can be cruel to coop them up in a house, but i have no experience in indoor cats)
many thanks
jenny