As has been shown by
Cabin Fever, there is a choice to tell Derek whether you still have feelings for one or the other if you are rejected by them, and this has a variable attached to it which wil undoubtedly be recalled later on. So there's definitely a chance as there's always the possibility that their relationship implodes again and one or both will come running back to the MC and they will then have the choice to choose which one they want then, maybe even have another go at the throuple if they (M&J) feel that they made a mistake not accepting him before and that they're better off with him than without.
I think their feelings for the MC could be the reason why they might break up/have difficulties if they're not in the throuple because in that scenario, they both do want to be with him but they're each too afraid to admit it in case they hurt the other person's feelings.
M&J are a package deal right now because they are in a relationship with each other. Even when the MC was doing things with them individually, they were still in a relationship because they hadn't formally broken up, and in ep 4 the renew their relationship with each other. So it would be kind of a dick move by the MC to be like, "nah, I just want Maya, so I want you to break up with Josy so we can be together".
There will be a reason for this and it's importance to the story has yet to be seen, so it's either both or none at this point and we all just have to accept that.