I only used salt for seasoning, nothing else. When I cooked it properly and it became very soft I had no issue, but half raw I had. I also didn´t over on it. I just had one small piece which becomes tiny once cooked. Almost like oil. I could eat it only by itself, but I would only consider that when I will get a healthy source. I´m a bit fed of up experimenting and feeling like shit all the time 
So you salted and cooked the bone marrow? No wonder it tasted fine, any grain-fed/CAFO etc... animal food which otherwise might potentially taste horrible or at least worse than grass-fed/wild game can always have its taste masked by cooking/salting/seasoning etc... There are studies, which have been done, which show that people prefer the type of meat they grew up with... some preferred grain-fed, some grass-fed. These were all done on cooked muscle meat, so it makes sense that grain-fed tastes a lot better cooked/salted/seasoned than raw, and this applies to organs as well.
In the case of bone marrow, I'd say it's much better if it's a good quality animal and if it's raw, unseasoned, just speaking taste wise and texture wise. Obviously not cooking it is better from every other perspective as well, including the ability to tell by taste (or at least in almost every case I've seen, but perhaps there are some exceptions, given that people may perceive taste in drastically different ways) the quality of the meat.
And you seemed to mention you can't digest raw foods well? If that is true (for muscle meat and other lean organs), then fat (including bone marrow) should be very digestible raw, as it is not digested in the same way as protein. That is assuming, of course, you also do not have a separate problem with the digestion of fats. I am curious, how do you know you can't digest raw foods well? What kind of self-experimentation/tests have you done?