The way I understood it is that he still had some feelings left for the ex, but was already in love with Wataru. That usually happens when you jump from one relationship to another too soon. It's not like he wanted to come back to his ex, but he still had some leftover feelings. Still, Soma's EQ is fucking awful, I'm impressed by how tolerant Wataru can be
I wish the writer could have made the plot and soma character coherent to clear up the confusion since he's saying one thing to Wataru and something completely different to Yoshida. If he were completely over Yoshida like he claimed then there would be no need to invite his ex to a personal celebration dinner that was for Wataru's achievement in securing a career. I guess Soma's character was just all over the place saying things and inconsistent for me
Is anyone else confused? In chapter 5 Soma says "I'm not in love with him...is what I'd like to claim, but I don't think I can" he's talking about how he still is in love with his exboyfriend Yosida but he also asks out Wataru that same moment.....and in Ch 6 Yoshida says during their new years hang out, soma told him "the moment I asked Wataru out was when I completely moved on from you". so what is the truth..the new years hang out was way before Wataru dyed his hair black too