But then of course, we both caught feelings for each other. 

The only thing that is really stopping it from going any further is his own past and relationship history. Even when we were friends, he wasn't a very open person emotionally. As we started getting closer though, he's opened up with so much and I know it's because he's having feelings for me (as he's told me). But, his last serious relationship was with an ex fiancée, and that ended only a year ago. He doesn't have feelings for her anymore, but he's admitted to me that he still misses her (understandably) and that it's ruined other friendships and he has self sabatoged relationships because of it, but he's trying really hard. He talks about how much he likes me and being with me and getting to know me and the time we spend together alone, coworkers, and when we're out with mutual friends. I know he needs time is all. I understand it completely; I've been in the same exact position he was in three years ago and have only just now been able to "move on" 112% from what I had. I guess what I'm seeking advice for is to know what to be doing while stuck in "relationship limbo"? Where we both have cut off contact with other FWB, do not seek out new people to date/sleep with, but aren't really "committed" in the sense of "im dating Amanda"? How do I know when I should be able to cut my losses and run (it's only been about a month since we've started exclusively seeing each other outside of just having sex, and literally a whole week until we have both admit to having the ~more than FWB~ feelings with each other)?