The first thing you should do if you want to work on maintaining a healthy balance between the two is figure out what it is that you need in order to feel like your life has enough balance. It's important to know yourself and how you function best in order to maintain this sort of lifestyle.
For example, I need my weekends completely off. Not just a few hours here and there, but an entire day to do whatever I want without checking my phone or thinking about school.
Without this structure in place, I'm not happy. It's not feasible for me to have a work-life balance if I'm taking calls after 6 p.m. on Friday night or spending my weekend doing homework and writing papers. I need to be able to block out my work life in order for me to feel like I have a personal life.
A lot of people may think this is extreme but it's how some people function best and you should never feel bad about demanding what makes you happy as long as it doesn't hurt anyone else.
The second thing you should do is figure out your priorities and what's important to you. If a job has too much work-life balance, it will be difficult for me to get ahead in my field. I need to be working long hours in order to stay on top of the game and make connections with influential people--with a work-life balance, I would lose a lot of my motivation to be successful.
At the same time, if I'm always working, it's going to be hard for me to maintain meaningful friendships and other relationships. Balancing life is all about finding that middle ground where you're comfortable in order to feel happy and healthy.
So, when you're figuring out your game plan for maintaining a career and relationship with a significant other or friend, figure out what's important to you. What would make you happier? More free time? Or more money? And is one of these things more valuable than the other in your eyes? Because then that will tell you where to focus your energies the most.
It might be tempting to work as much as possible in order to make more money, but if you do that, your relationship with your significant other could end up suffering. So it's important to figure out how much money is worth sacrificing a healthy personal life for because every dollar you earn has a price--your happiness.
Even if you think that someone is worth being unhappy for, why would you want to choose unhappiness? We all deserve to feel happy. Happiness is what life is all about and it's better to be happy than anything else; money can't buy happiness.
Now, the last thing I'm going to advise on here is that you learn how to say no.
You can't do everything. Even if your boss doesn't expect it, it's good practice to start saying no now. It's bad for you mentally and physically to overwork yourself like this--your body won't be able to take it! And especially if you're not happy in your position, it doesn't help you to keep putting in all the extra hours. If you're not happy, don't be afraid to quit!
If you really want to work somewhere then try asking for a promotion or a raise before quitting. Chances are they might give it to you if they like your work ethic and then that will make it worth your while!
But if you don't get it, then quit and move on to something better. You don't want to waste your life at a job that doesn't make you happy or challenge you. When it comes down to it, there are no benefits to staying in a job where you're unhappy for long periods of time--the only thing you're going to get is more unhappiness when you realize that nothing will change.
So don't be afraid of rejection and take a risk! If it doesn't work out, at least you tried--and nobody can fault you for trying. Do it now before your boss gets too comfortable with having you around all the time!
Now you should be in a much better position to ride your career and relationships together like the perfect tandem bicycle.
The most important thing is just to remember that you can have the best of both worlds, as long as you're willing to work for it. It's going to take some effort on your part, but don't worry I'm sure everything will work out in the end if you just believe in yourself.
And, most importantly, remember to always be happy and love your life no matter what happens--this is something I wish I knew when I was younger! It's not worth being unhappy for anything or anyone. You can only control one thing about your life and that's how happy or unhappy you are. Don't forfeit your happiness just for a better paycheck or to impress other people, because it's never worth it!
If you follow this advice and believe that there's nothing that can stop you from being successful in both of your careers and relationships, then I guarantee success will come to you!
I hope this helped and good luck on your future endeavors!