Right. Let's study the 'evidence', shall we?

Misto/Vicky: they do the Invitation together. They sit next to each other during Gus the Theatre Cat. He makes her appear and then smiles at her during his dance number. They stand next to each other and look at each other once during Grizabella's ascension.

Misto/Tugger: they stand next to each other in the 'pyramid' during Jellicle Songs. Misto sings a line in Tugger's song describing him as a 'terrible bore'. If he truly thought this about him, though, don't you think it would've been a bit more obvious? We all know the death glare he gives Grizabella as she exits the stage the first time, so if he was really all that disgusted about Tugger, wouldn't he have done the same? No, instead, his tone is almost sarcastic and he simply rolls his eyes as he leaves -- almost in an affectionately teasing manner. Seems more like flirting to me, don't you think? And Tugger certainly doesn't seem to take any offense to the line, either. Then, of course, there's that split-moment encounter during the Song of the Jellicles. Moving on to the second act -- Misto's number. In other words, the only song that Tugger actually sings other than his own. If Munkustrap is the narrator, why doesn't HE sing about Misto? The fact that Tugger, who we hardly actually SEE in the show other than in a few important songs, is taking Misto's entire number as a solo suggests that there's something deeper going on between them. From the introduction to the song, it becomes clear that Tugger obviously has quite a high opinion of Misto and the things that he can do. The way that he sings the entire first verse is quite flirtatious, and even the slightest bit sexual. All the way up until Misto's solo dance, Tugger keeps following him around the stage and mimicking his moves almost playfully. He seems quite enthusiastic about Misto's tricks, and encourages him when he can't get his lightning to work. He watches intently during the entire solo dance, and whole-heartedly urges him on during the bit where Old Deuteronomy is brought back. And after the old guy is back, simply the tone of Tugger's voice while he sings the chorus says more than words ever could (granted, this one can be a bit more obvious depending on the production -- I've heard some versions where Tugger sounds undeniably infatuated). Same goes for those long notes he holds out toward the end of the song. And be sure you take a look at some of the faces Tugger makes throughout the entire duration of the song! And then finally, at the end, he concludes with "I give you the magical, marvelous, Mister Mistoffelees!", while Misto sort of plays along with him as he sets the stage for Misto jumping off the tire. Tell me, what other character gets such an affectionate grand finale like that? The song almost always gets one of the longest applauses out of the entire show. I should know -- I've seen it live twice.

If this is truly the Misto, Victoria, and Tugger you're talking about, I believe you've talked yourself into a corner.