If i'm not mistaken your MC can romance Malcom alone but he will eventually enter a relationship with Milo too, and the same thing happens for Milo route. You can do their solo route but your MC will always end up in a polyamorous relationship: either a V poly (where you dating one of them and they're dating each other) or a triad poly where you're dating both of them and they're dating each other so basically the three are together.