The reason for sticking around after mating is to protect your children. In this sense, there is definitely an evolutionary pressure to live longer. The longer

The reason for sticking around after mating is to protect your children. In this sense, there is definitely an evolutionary pressure to live longer. The longer an organism takes to mature, the more advanced it can become. Consequently, the longer you live as a mature individual, the longer you can mate to produce more children and protect the ones you already produced.