I'm devastated to find out that Aeran's not a LI :sob: I only read that recently even though MC and him are SouL MaTEs
Viewing post in Official Episode 2 Discussion [SPOILERS]
Not all companion characters are LI but there are characters that are not part of the main gang yet can be romanced. There also will be characters with whom you can just flirt with or have one night stands with, without them being really LIs. So yeah, just because you can sleep with someone, they might not be romancable.