I think as a man, I prefer not to share my prob with my gf (if hav 1 lor) if i can solve the prob myself. however when i tell her, it means that i need suggestions/solutions not only to tell her the prob.

So as to answer the topic ; no need to understand ur bf fully, just understand him to the parts that he wants u to understand him ; when he ask for ur view, do not give some nonsense answers or else he will not bother to tell u anything anymore ; give constructive answers and IMHO the most important thing is that do not ask him too often about the prob.
Thank you