"We have been together since a young age before GCSEs and I have supported him through GCSEs, Alevels and now his degree."
I see two possibilities for why you have taken on this support role:
- You are a people pleaser, always putting everyone else's needs and wants before your own, probably because you do not value yourself and see your own needs as lesser than those of other people
- You view him not as an independent autonomous person but as some sort of exotic pet, to be micromanaged and chivvied into performing for your pleasure
Neither scenarios are healthy.
"We are supposed to be getting married next year but I fear that if he can relentlessly lie like this for 5 months what else can he lie about.
Do I have a right to feel upset? Am I going to be able to get over the complete lack of trust? AIBU to feel so hurt by this ?"
Of course you have a right to feel upset. There was a cost to his lies, a cost that you bore in time spent 'supporting' him when you have no time to spare and emotional labour in trying to facilitate him. I would be more than upset, I would be absolutely furious with him about that.
You are right to consider whether you can trust him, because his lies involved real effort - fake files etc. And he must have been aware that you trying to take pressure off him placed a burden of time and effort onto you. That burden was less important to him that the maintenance of his illusion that he was progressing.
BUT - and it is a very big but - step back for a minute and ask yourself WHY. Why all the lies?
From my perspective, I see a young man who frankly is not academic. "He struggles with being under academic pressure and never seems to start essays until they need doing". It sounds as if this has always been the case, all the way back to school, GCSEs, maybe even before then. So why, I ask, is a young man who is not academic, who you say will not use his degree if/when he gets it - why is he at university at all? What pressure to be there is he under?
I realise that there is a certain taken-for-grantedness these days that all young people should go to university if they have the entry requirements. Is that how it went? His parents, the school, you, his friends - did you all just take it for granted?
And since I've raised things being taken for granted - you plan to marry next year, at the grand old age of 23? Have a think about that. A real think. I'm not saying you don't love each other, but I am saying that you are not ready for that. He needs to find his feet in the world and not just do what others expect of him (he may be a people pleaser himself). You both need to stop following this pre-ordained path.
And you definitely need to step back from micromanaging another adult, whatever the reason you have for doing it. Otherwise you'll never really know who he is, and he will never get the chance to grow up.