The sun is expected to grow in brightness over time, slowly heating the Earth until the oceans evaporate, leaving the planet uninhabitable.
Jupiter is the source of the largest perturbations to Earth's orbit. In general, the 3 body problem (and higher) is not stable. So we can expect Jupiter to, eventually, perturb Earth's orbit until Earth falls into the sun or gets kicks completely out of the solar system.
So, which do we expect to kill the Earth first: solar baking or orbital chaos?