To doubt he's actually 'sick' again in time for our Easter plans?

Assuming he's being honest, I'd be worried that he's always going to need time alone. That if we lived togther he'd be squirreled away in his office the whole weekend because he needed it and I'd get the crumbs of his time. It's not that he's doing anything wrong, it's an issue of compatability.

Op Forgive me I am being frank here but the longer you stay the worse this "illness" will get.There are a million and one posters on mumsnet who will tell you the same, who have posted the same. This man is not ill, but what he will do is suck the life out of you subtley. You research the various threads. I will tell you what happens when it starts like this..every big event,every thing important to you will become controlled by him. He will be ill when you are desperate to go to the concert,ill before family come for christmas, ill before you are due to go to a wedding ,on and on it goes like a dementor sucking the joy out of your life. It starts like now and trust me it gets worse.There will always be something come up when you are looking forward to something.I promise you it will. He will always become suddenly.unexpectedly ill just as you are ready to go.Please look through some old posts on here you will see whats happening is laid down by so many other women too. I have no wish to upset you but its a very real thing and so emeshed. Just for the sake of you and your happiness and mental health leave this relationship now. You do not need to experience what will happen further on. I am sorry.

He is leading you on. He has plans with other people/women. Dump him and do something nice for Easter and tell him to fuck off.

Sounds like a combination of things plus bad timing.
If he's just handed in a PhD he's probably completely burnt out. When i handed mine in I didn't want to see or speak to anyone for a couple of weeks and I got ill because I was so run down.

Doesn't mean you should hang about waiting for him though.

Why would you prioritise this non-committal boyfriend over your friends who presumably has been there for you reliably for a lot longer? You and your friends should be more important to you than a guy you have been seeing for 4 months who can only see you if everything is perfectly aligned. I wouldn't treat my lovely friends like that ever.

Op, it’s not the ‘why’ he doesn’t want to meet more often. He just doesn’t. If this is enough for you, then accept it and make your own plans without hanging around to see if he decides he wants to see you. If it isn’t enough, then move on. You keep trying to justify why things are like they are, but whatever the reason - they are.

Obviously everyone can make their own choices but I wouldn’t be sat waiting around waiting to see if someone could muster the energy to see me last minute when I could be seeing my friends.

You've only been with him 4 months and he's making a load of excuses not to see you already eg family/phd/ill. This should be the 'honeymoon' phase of wanting to be together. I'd bin him, he's flakey and not that into you sadly.

If he is on the spectrum he more than likely needs time to himself. Maybe ask him if he like to meet for a few hours on bank holiday Monday. That gives him Saturday and Sunday to himself. He should be refreshed by Monday. Also see if any friends are available.

Errors here include:

Thinking of him as your boyfriend
Believing his words instead of his actions
Trying to convince yourself and us there's something to build on in this relationship
Not having binned him off already.

Advice:
Text. 'OK, Got it. Bye.' and block, block, block. If he sends mail, flowers whatever, straight into the bin. Don't read them, don't keep them. He's had sixteen weeks of your precious life. He hasn't made you feel safe and secure. When he's with you, it's all fine. But he isn't often with you, isn't reliable, doesn't prioritise you.
He's not the one. Raise the bar, don't lower it. You are worth more than this.

Stop making him your priority, you’re not his.

Don’t sit around all weekend doing nothing just in case he decides to get in touch.

Go back to the friends/family whatever plans you turned down, say your plans have changed and you’d love to do xyz, then message him back and say you’ll see him another time.

It’s unfair of him to keep you hanging with potentially nothing to do all weekend, make your own choices.

I agree with the others who say you are just not a priority to him. More than that - you are someone that he feels will be overwhelming to meet when he's had a busy, happy time elsewhere and therefore he will cancel you.

I would not settle for this. At this point, I would not text him again until he lets you know his plans - and if he's not coming at that point I would send this message.

'Thanks for letting me know, Jack. It's become increasingly clear that you are not that interested in spending time with me. It feels increasingly flaky and that I'm dropped when you can't be bothered. I'm not interested in a relationship like that, so I'm calling it a day. Don't bother contact me again. All the best, Celia'.

I know a guy like this! He's a great big hulk of a fella and everyone loves him, but he's also really flakey and likes his own company. He isn't relationship material. You are tired and need a cuddle from your supposed bf. He is tired and doesn't want you anywhere near him.

Guys like this are great when they're 'on' but mainly want their own company. It only works if you are the same and you aren't.

Think you need to move on (and yes, I think he is not that ill - if he truly wanted your company he'd probably push through and keep your plans)

It shouldn't really be this difficult after 4 months.

Cancelling when your ill is reasonable but it's the last minute of it, the fact he didn't say it until you brought plans up and that he's not mentioned being ill or it hasn't impacted on his ability to do stuff otherwise.

It reads like an excuse. It could be he wants time to himself, or he's not that invested in the relationship or he doesn't want to appear too committed to you.

It's the way he's done it that would annoy me. Four months in should be fun, ripping each others clothes off. Not worrying why he seemingly doesn't care about seeing you.

I'd question if you guys are in the same place. There's no point being either way someone who makes you feel lacking.

Are you long distance? I only ask as it appears you can only see each other weekends? I think with LD relationships, they definitely feel more casual and fun.
As he's ND, I'd give him a chance and let him know how gutted you would be to not see him for the long weekend and how much you were looking forward to it.

I was going to say this but now you've mentioned it.
Sometimes people who are ND can begin to feel themselves start to become overwhelmed. Because there isn't always a particular "reason" they find it difficult to articulate it, and so use other easier examples, such as a migraine.
It might be that he does have a migraine too obviously, but I'm just telling you that attempting to communicate something that

NT people don't experience, isn't easy, so sometimes we translate it to something easier to understand.

You aren't partners, you've been seeing him for 4 months, and not very seriously by the sounds of it.