I'm going to echo Ciel here. Can you elaborate on the problems you faced with your boyfriend? "Relationship broken, add people" works in very rare cases only and only if yore working on the problems you have instead of hiding them by adding people.
As far as the mood changes, I understand what you're saying. I'm that way too. It's not a swing if there isn't a swing back and forth. I hear you on the conversation and the neediness and the shows and all of it. My profile on another site says, "I'm married, have children, live a polyamorous lifestyle, and a huge nerd. I find myself interacting with electronics more than people. Know what? Electronics don't judge me."
Welcome to polyamory!
"Regret for the things we did can be tempered by time; it is the regret for the things we did not do that is inconsolable." - Sydney Smith
Kyle: 27 year old male
Katie (rymmare): 25 year old female
Kids: girl: 5 years old, boy: 3 years old