Who is to say that it will even end peacefully? The West would have propped up Francoism indefinitely, and would have been fine with a fascist Juan Carlos. They would not do anything to bring Mussolini down, and would want to keep him strong lest his communist opposition spearheads a revolution. Italy may have trouble with colonial insurrections on one hand; on the other hand, as long as it can keep Libya down, and has found the oil in there, it could probably survive as a petrostate. It's anyone's guess when it all comes crashing down.
There is a lot of difference between the situation on Spain (or germany or russia) and Italy.
Benny, not even at the moment of greatest influence, did have the same power of Franco, Hitler or Stalin; in the italian political life there were a lot of other important and influent actors like the King (and the army) and the big businessman.
To this add his habit of surround himself of yes-men and people who get all his legitimancy from him and without it are nothing; this will not change even in his last years, probably it will become worse...basically see the implosion of Forza Italia in Italy with Berlusconi (that in the previous years progressively sent away any possible successors like Fini and Alfano) effectively out of the picture for judicial and age reason.
Once Benny hit the bucket (or can't govern for other reason like health or...things that happen
) the number of people capable of taking control of state can be counted with a single hand...and even in that case who's in charge will have less power than Benny.
It will be more or less peacefull due to the fact that the other political actors in the nation don't want any serious trouble and even the other nation (if Italy remain neutral in WWII, mean that she is still one of the big boys and nobody want that kind of trouble...naturaly an italian neutrality in the war change a lot of things and so the world political landscape will be hugely different).
Regarding colonial conflict, the only serious is in Ethiopia, the rest are widely pacified, fully on the road to have a big italian minority (Eritrea) or majority (Lybia), not counting that Abyssinian freedom fighters will not be liked in both Somalia and Eritrea (frankly between having to be part of Ethiopia or having to face it and being part of some commonwealth-like agreement with Italy they will probably choose the second).
Said that things in Abyssinia will become ugly, the Duke of Aosta unlike his predecessor tried OTL to reach the locals and build somekind of legitimancy and respect, still in 1940 the country was not fully pacified and things were much on flux