snubber push pull
Let me to get back to your original question:
but due to this spike my Mosfets gets too much hot.
The conclusion is most likely incorrect.
And regarding the suggested snubbers:
it also gets heat up... and broken down......
Snubbers are dedicated to absorb energy. So it's basically normal, that they heat up. The trick is in adjusting the time constant and impedance in a way, that they only (mostly) absorb unwanted high frequency oscillation energy and little at the SMPS operating frequency. Because the ideal converter waveform is a square-wave with unlimited frequency spectra, this is impossible in principle, so the snubber dimensioning is always a compromise.
As long as the spikes must not be feared to damage the switching devices, they are mainly a problem of generating interferences, but they don't cause excessive losses.
Recent MOSFET have typically integrated zener-diodes, that clamp spikes above the maximum Vds. This way, the energy stored in the leakage inductance is turned into losses. Absorbing the energy in a snubber can only increase the total losses. You either have to use a transformer with less leakage inductance or a switcher topology, that recovers the energy at the primary. A classical two-transistor push-pull converter can't, unfortunately.