Choosing between love and career

I am facing thirties and all I have in my resume is mainly studies. I like research and that is why I want to do a PhD in a field I am interested in. The problem is that my studies don’t pay my rent [so I live with my parents] and every time I decide to make a new step in my life strangely enough I fall in love. Lately I fell in love with a man who was in a relationship and broke up after meeting me, and we like each other.
The problem is that he still feels bad about his breaking up from his long lasting relationship, but as he admitted it was holding him back. And this is not the only problem. He lives in another country, a couple of thousand miles away. How can I decide to move to his place when I am not sure about his feelings?
And what about my studies and my future which I am neglecting ever since I met him? Will it always be like that? Falling in love and then failing in my personal life? Is there a particular helpful book I could read?