The destruction of the temple and the parousia were not separated in time in Jesus' prophecy.
The only bit he got right was that Rome would attack Jerusalem - hardly a surprise. His followers have been inventing increasingly contrived excuses for his failure ever since.
For brevity here is an edited version of Mark 13 which was the source for Matthew's and Luke's gospels. Read the whole chapter online here...
I challenge anybody to claim Jesus did not tell his followers his parousia would happen in their lifetime.
Not one stone here will be left on another; every one will be thrown down.
Tell us, when will these things happen? And what will be the sign that they are all about to be fulfilled?
Jesus said to them: .. Many will come in my name... wars and rumors of wars.. Nation will rise against nation..earthquakes in various places, and famines.... You will be handed over to the local councils and flogged in the synagogues... the gospel must first be preached to all nations..... Everyone will hate you because of me, but the one who stands firm to the end will be saved.
When you see ‘the abomination that causes desolation...flee to the mountains.... If the Lord had not cut short those days, no one would survive. But for the sake of the elect, whom he has chosen, he has shortened them.... For false messiahs and false prophets will appear.. So be on your guard;
But in those days, following that distress,
“‘the sun will be darkened,
and the moon will not give its light;
the stars will fall from the sky,
and the heavenly bodies will be shaken.
At that time people will see the Son of Man coming in clouds with great power and glory. And he will send his angels and gather his elect from the four winds, from the ends of the earth to the ends of the heavens.
Truly I tell you, this generation will certainly not pass away until all these things have happened. Heaven and earth will pass away, but my words will never pass away.