I can see Beagle because neither of them were really knowing what everything was about, and college is for experimentations. Only of course Ellery fell hard with his heart, but they never really had any communications, it was all supposed. It happens.
I look at a Gabe as a fuck buddy. Nice enough looking, fills a gap, doesn't make demands on a regular basis. Have had a couple and they certainly did fill a space, but were never anything that was going to go anywhere, and I don't think Ellery ever considered having it go anywhere, it just was when it was and then it wasn't.
Bill---I think Ellery thought they had more in common, and truth be told---I think ellery actually could tell the needy part of Bill, and it also answered something within Ellery, but what he didn't realize was the basic instability of Bill, and what an advantage taker user he turned into---but by the time Ellery found out how untrustworthy Bill was, it was entirely too late, he had just let them become entwined through business and emotional connections. Ellery had a real problem of having to admit he made a bad choice. And that is not easy, it sucks, and sometimes it is easier to just let the connections stay than going through the reality of severing them.
Been there done that---Ellery was knowing he was in a dead end situation with Bill, but until Bill did something illegal against Ellery, El just couldn't go through the scene of trying to be free of him. Ellery is the law and that brought its own built in set of morals and principles that Ellery would never turn his back on, and those are what gave him the spine to finally get rid of Bill. Sometimes it takes something just that drastic.