I had a gf that was super controlling and did the same ( not comparing the gfs) but it was a bad situation i did everything i could for her and bam i still had no freedom the moment i was doing something for myself i get scolded luckily i just found a new gf and she loves going fast score for me
but anyways he should be able to vent elsewhere cause we all know if we dont get our thoughts straight before going to the significant other and telling her someones bound to get super pissed cause even if your in the most open relationship someone will get mad if you say EVERYTHING thats on your mind before you have cooled down thats why you have friends..... or a forum
p.s. no one is judging the gf but the fact she had to hop on here to at least get her word in kinda would scare me ......