Hmmmm I wouldn't mind Tita and Clete together. This isn't really incest. But I would've prefer having them with just a mother-son relationship. Imagine if there was actually another guy destined for Clete. It would be funny having her future hubby and protective Tita playfully fight over her.
Anyway, this kind of relationship reminds me of Inuyasha where Sesshomaru fell in love with Rin (plus the age gap lol).