There are many things I could say here, but to focus the issue I should really rephrase the question: why do I remain a Christian?
The answer is fairly obvious: Jesus of Nazareth was resurrected from death. This is part historical truth and part theological reality. The historical truth is quite easy to prove. Bart Ehrman’s excellent book Did Jesus Exist? absolutely smashes the stupid claims of mythicists (it is charitable to call them stupid for truly they are in fact evil). But he comes to what should be a troubling conclusion for a non Christian historian such as he: the disciples believed that they saw Jesus die and then they believed they saw him return to life. Yet Ehrman remains deconverted from Christianity, as he is unsure how to understand the experience of the disciples. But this piece of history seems relatively easy for me to interpret: after suffering death on the cross Jesus was raised to eschatological life. Lazarus died again. Others who had been brought back to life had eventually died again. Jesus would never die again. Resurrection is the thing that will happen to all people at the return of Christ and the consummation of all things (this is one of the many one reasons I’m not an annihilationist) and resurrection means more than simply breathing again it means the totality of your being is brought into a new reality. Jesus was the first fruits of this, he brought in the final things through his resurrection but the rest of creation awaits her redemption.
This is why I remain a Christian: Jesus was resurrected from death. The mythicists are wrong. The atheists are wrong. The Unbelieving Jews (as opposed to Messianic Jews) are wrong. The Muslims have shadows of this but can’t fully accept Jesus as messiah or his resurrection. But the simple record of history can’t be understood satisfactorily without this conclusion. This is all I need. To paraphrase the inestimable Pelikan: if Jesus has risen from the dead nothing else matters, and if he has not then nothing matters. Paul basically said the same thing 2000 years earlier and it will remain true 2000 years after Jesus returns. He is what makes life worth living, and he is the one who will give us “life after life after death.”