This whole part of the story is a bit of a mess because the intent is to make Emily and Santiago come out as the good guys and Andres the villain. There's a scene in the restaurant where you can see Emily on the phone with Andres where he presumably tells her that yes he started dating her to spite Santiago but only at the start and voilà, instead of Emily realising that eh, he might have wanted to get back at Santi but he still married me and took care of my kid, but no- now she has a reason to really hate Andres.
Meanwhile the plot almost completely ignores that the dude raised a child that wasn't his own (Emily does bring it up but the MC doesn't ever show any gratitude) and he for some reason attacks and throws out the kid he lived with and was a father to for who knows how many years over a fight that was his own fault. And to top it all off he's cheating on (or at least lying to) the woman he wants to marry. Oh and not telling your son that he's not really your son within this specific timeframe is bad because reasons.
Most of these older characters, if not all of them, did questionable shit as youths (Santiago most of all) but Andres seems to be the only one who's getting the shit end of the stick by being made the scapegoat for Emily and MC's problems.
But hey, DRAMA!
