If it`s not too late, here`s what I would do.
Strain the sauce to separate the meat and sauce. Put half the sauce into a pan. Add PASSATA to make up to the original quanitity. Warm, taste and adjust either with more passata of more of the original sauce. Return the meat to the pan. Now this is just a general guide - only you know just how hot the sauce is and how much you want/need to tone it down. If you`ve got the time and the patience, you may want to "fish out" some of the chillies as you add the meat back into the pan.
Other ideas, remove some of the sauce, add stock and thicken to the original consistency with some cornflour mixed with cold water. Keep any sauce that you remove and use it to make patatas bravas. Potatoes are well known for their capacity to take the heat out of dishes - this is why they are one of the traditional accompaniments to Goulash. This brings me to another idea - thin out the sauce with some stock and then thicken with potato flour - from memory this should be treated in the same way as cornflour, i.e., mix with some cold water, add some hot sauce, stir and return to the pan.
Hope this helps, if not for this time then next time - no, there`s not going to be a next time is there!!!!!