I think Executive Assistant is one of those job titles that can mean anything or nothing. It very much depends on what the company/manager needs it to mean! It often seems to be used interchangeably with Personal Assistant. If you are applying for specific jobs there should be a job description. Otherwise, it can vary depending on whether you are working for an individual or a team.
Generally there is lots of diary and meeting management, minute taking, travel arrangements, expenses, collating of e.g. Board papers, acting as a "gate keeper" etc. I have been an EA and worked for a fairly high-profile individual whose work and life were intertwined so there was also a lot of personal admin - Christmas present buying, doctor/dentist appointments, arranging holidays, concert tickets for her daughter, car servicing etc etc. It's useful to know before you start the role if your employer will keep their personal admin completely separate or not - some people love undertaking it, some hate it, which is unfortunate if you end up spending time sourcing a particular kind of cashmere jumper or buying a birthday gift for a 5-year old!
Nowadays, few companies can afford/value having people in purely admin or support roles so often an EA will also have some responsibilities in e.g. HR, contract agreements.
I don't understand your point about how it would work around your personal life? It is no more or less likely to impact upon that than many other roles. What do you do currently?