The risk of complications does increase each c-section you have, thats pretty well documented.

My sister has had 4 sections herself with no dramas, and the recoveries are better each and every time. Her OB has never set a limit on how many she can have either, so I would say its down to the individual person as to how many your body can handle.

I don't ever think its selfish to want another child - children bring a lot of joy into your life, so I don't see the selfishness of wanting another little bundle of joy