If I may, allow me to add a similar story of my own, and what it taught me.
My first wife (henceforth to be referred to as The Beast) and I divorced quite amicably in 2001. She moved about 250 miles away, back where she grew up and was comfortable. We have seen one another one time since, shortly after the divorce became final, to clear up some financial matters and such.
The Beast was and likely remains highly codependent. She has some serious issues in her life to deal with, not the least of which is a schizophrenic mother. As I have said on here before, I used to be a mental health therapist and worked in that field for over five years. For some time after our divorce, we emailed one another periodically (maybe once a month or so), she called me a few times when her mother went a little further off the deep end than normal, or when matters related to our marriage required it. Things like needing something from income tax records when one of us purchased a vehicle, credit records, things like that. At no time was there any real discourse regarding our marriage. We were both where we wanted to be, and were making new starts.
Eventually, The Beast met someone and ended up marrying this chap. I too met someone, we lived together for a couple of years before getting married. My current wife was initially OK with the limited contact between The Beast and I. For my part, I never initiated this contact unless vital, and never made a single attempt to conceal it. Usually, my (now) wife would be present when I read any emails from The Beast.
Then things started getting weird. The Beast and her beau bought a house...less than three miles from the one she and I owned...built by the same builder...same floor plan...almost same color schemes. Kinda weird, but maybe she just ain't all that creative, right? There were several other little things like that which I found pitiful, and my wife found disturbing. Then she got a dog...same breed as mine, a Basset Hound. While never cruel to my dog, The Beast showed only passing interest in him when we were together. Mine I named Elvis (he ain't nuthin' but a hound dog...); she named hers Presley. That was it.
My wife and I talked, and she let me know that things were starting to freak her out. Too much re-creating the prior marriage in her new one. After we talked it out, I composed an email to The Beast and told her that I though it was time to move on and begin breaking the remaining ties. The reply I got was, shall we say, disturbing. That's when my current wife took over,
with my full blessing. The email she sent to The Beast was very clear in its spirit. Needless to say, there has been no more contact, and I don't anticipate any more.
Point being, one can indeed hold on to former flames for a time. Some, I hear, manage somehow to remain not only civil but actual friends after parting ways. More power to them. My experience tells me it ain't worth it. There comes a time when memories need to be no more than that...memories. While I understand your beau's feelings, I do have concerns as to his method. Seems a bit forceful and domineering. If that is a product of his frustration, that's one thing. If it's more a product of his standard personality, that's quite another.
It's entirely your business, and how you handle it is entirely your choice. You know the people involved far better than I. But since you asked for opinions, I gave ya one. Hopefully, your X is not as...umm....challenged as mine was/is. Good luck with it, and whatever you do, do it for yourself, not someone else. So long as you do that, the rest will work itself out.
Oh, and if that time ever comes with the current beau....make sure you return the favor with an equally appropriate text message.