Your lover might start seeing their relationship with you as an obstacle to their chosen work, because the way that you lead your life is in direct conflict with the way that they need to advance in their career. Maybe they need to be out there in the public, networking with the VIPs, promoting themselves and creating a very specific and well-crafted image of themselves ... and you just want to stay home.
Or perhaps they need to travel a lot to get their career off the ground, and you need to stay rooted in one spot in order for your work to work out. You have needs that could turn into demands or even ultimatums when they aren't met. You have to come to some kind of agreement, but that isn't easy, especially if bad feelings have sprung up as a result of your different aims in life. You might both end up having to ignore the issue altogether if you want things to work out between you -- just don't talk about work at all. But that's no fun, and it's hard to ignore such a big part of both your lives. If you can move past any hurt feelings -- even if it seems as if your lover puts their career before you -- and talk things out, you might be able to strike a compromise that works for both of you. It takes a lot of communication and dedication from both of you. If the relationship's just a short-term liaison, it might not be worth it.