Should i reconsider

I would question his boundaries as they seem a bit loose. As long as he respects yours I guess.

Are you comfortable with your husband remaining in touch with his ex's family? If you are then the probability of you running into her at an event is fairly high. If you aren't then you need to have a conversation with him about that. Honestly I think it would be more awkward for the x than you, seeing someone you used to love with his new love (let alone his wife) is not easy. If you decide to go just be kind and remember he has chosen you. Best of luck to you.

In my personal opinion that is not okay.

1) I don't understand why your husband's ex girlfriend's family would have wanted or needed to be at your reception, that's odd. Plus "show the same support back to them" by going to a Super Bowl party, support for what? Just plain NO. He was supportive to them when he was with his ex, but that's been over, as it is time for him to let go of them as they are a part of his past not his present time. You are his present time in the moment and that's what he should be thinking about. Not hanging out with them. Especially if his ex plans on being there, as there is no reason for any of them to "mingle" anymore,

2) Would he find and deem it okay if the roles were reversed on this?