spreading the information

I am a account that my husband has set up and it has my kids accounts too. Weird things happen a lot between our phones like the other day i get a text message with a reply to a text message that my husband sent to someone? he received the reply too so it's not like it was just sent to the wrong person. Or one of the kids get a new free/paid app and it will show up on my husbands phone? I was just looking at my bookmarks and found that 20% of them where my husbands he has on his phone.? My husband says because we are on his icloud account but isn't there something we could do to stop this because if i buy a xxx rated app i sure don't want my son to know😉