Wow, You are truly in an awkward position. While it may be difficult to let him go, I would say that for now, that would be the most healthy thing for both of you. It seems as though he has a lot on his plate at this time, and you are simply starting out. Also, with an upcoming surgery, it is very important to take care of you. This care can be comprimised greatly if there are other serious things happening.
I wish you only the best. And there will be someone out there for you, just be patient.