I guess you boyfriend should had discussed with you about his further plan after PhD....
a simply 5 year overseas study, differs a lot from relocating to another country for a life-long career, and thus this affect the career & personal planning of another half significantly.
and thus if anyone that is mature and responsible do consider the current one as the life partner, one should had discussed this with his/her GF/BF during application. If not, well...we all know the story.
2. The reason why accounting is easier to be hired as an international students is not becoz of the technical requiremrnt, but somehow becoz it is too boring and thus difficult to find local to do it.
3. Non STEM = 12 momth OPT = only one time chance to lucky draw....when u have a full time job offer