Most Helpful Guy
I guess he would need to tell you why it was so important to him. Does he still have feelings for her? If so, he's worth losing, at least until he sorts out those feelings. You're going to be stressed out enough on your wedding day -- he should realize that this will add to that stress.
That being said, it's really up to you. He did choose to marry YOU, not her, so that should give you some self-assurance. He does, as I said above, need to talk about why it's so important to him, and why he feels the need to talk to this person for so long. After you're married, does this mean that he's going to be inviting her over to your house to visit? All of this needs to be discussed. I wouldn't be OK with that, but I'm male, and I definitely wouldn't want someone who's seen my wife naked besides me hanging around.
You need to set your own ground rules if you decide it's that important to him, and if he doesn't agree, I'd put things on hold until he thinks about it. Things like -- no dancing with her at your reception. No catching the bouquet or drawing attention to herself. This is YOUR day. You are being understanding and civilized by inviting her, but she has no right to take anything away from you.
Bottom line: if your fiancée is that freaked out about not inviting his ex, you need to find out why it's so important to him, and if he cares enough about you to want to marry you, he should be mature enough to have a discussion about it without walking out. But remember -- that means no yelling on BOTH sides, so be prepared to control your anger.
Good luck.1THIS IS NOT RELEVANT ANYMORE
Most Helpful Girl
Tell this so-called 'SO' which is a Supposed a 'Soul mate,' that if he plans on walking down any Aisle with you, a so-called "Almost wife,' to Dump this bright idea of Inviting 'An old girlfriend,' or he will be left standing at the alter With... No bride in sight.
I find it 'Weird' that he feels She should be there on Your Special Day here, dear. I do Not know What motive in mind that he has in his Muddled lame brain but he better ditch it or end up in the dog house, with barking up your tree with thee.
It's Not to Late with your mate to Cancel Her out with your own RSVP. And if he Continues down this boyish bad behavior problem path of having this hissy fit, making it a War of the Roses, Better now for Worse to find out Before the honeymoon than After About Someone you thought you really knew but Really... I Do Not.
He Needs to give this Ghost Away or Suffer the Consequences of Possibly Throwing the bouquet at hand, which is You, to Someone who may be more Deserving than Him.
Good luck. xx0THIS IS NOT RELEVANT ANYMORE