They teamed up for like one episode, what else ya got
I'm referring to same-sex relationships
1. He voted for her when they were picking class president, so she stood out to him, even back then
2. Momo has to be at least somewhat grateful to him for helping restore her confidence. During the final exams he reveals he voted for her because he trusted her judgement
3. When they leave to save Bakugo, one of the reasons she goes is to make sure they don't fight. The other reason? She said she trusted Todoroki's judgement.
The way their relationship has been progressing has been extremely similar to Deku and Uraraka, with the two of them helping and understanding each other. All it's gonna take is them realizing it or someone like Aoyama playing Hitch to make it happen. Bank on it.
And yes, I've thought about this way too much