Going to uni with a cat and my partner

Me (20, going into a bachelors) and my partner (22, going into his masters) are planning on attending uni together this year,

We've been dating for 4 years.

This has been an unexpected change as he got offered a full ride for a PHD, and we have realized after careful consideration that the opportunity better suits our situation and will give us both more opportunities, socially, financially, career wise and for our mental health as we've been so drained of life and had no opportunities to live life as all we do is work, try to build businesses and sleep,

So to the point, we have a cat, and rehoming/leaving him with family is not an option. He is genuinely our child and at this point, a lil emotional support guy for us,

My parents are estranged and I'm on my own in the UK, whereas my partners can't look after one,

We haven't decided on a uni yet, (he got full funding for Leicester. Unsure if he wants to go to Leicester yet.) although rumour has it, University of Leicester allows pets? Under certain pretenses? Can anyone confirm?

What are the options? Private tenancy sounds best but finding one bills included + under £800 a month seems impossible in this market (the most we could realistically afford on maintenance as per his experience) I guess the alternative is hiding him but we would need flatmates who are in on it and I personally don't know anyone IRL in the UK and any of my partners friends finished uni and moved on.

I'm feeling a bit hopeless as I think at this rate I will just need to work full time and support us while he studies so we can just rent normally with our lil Dexter, but it was my dream to attend university and I put it off to improve our life with full time work and supporting us, so it'd hurt a lot to need to choose this option again.

Would universities be more lenient if he was officially registered as an ESA as I'm diagnosed with certain conditions that could validate it? I know in the UK it's not taken very seriously.

Additionally, while I'm here, has anyone had any luck sharing uni accommodation with their partners? Almost every place I see says 'no couples' except for some accommodation in Wrexham which says you can get a shared room only if you know each other prior which might work best, I have straight up asked them about their pet policy too.

Thank you in advance!

EDIT: For the record, if it makes a difference, I've been working since I was 16 and renting since I was 18 therefore I can provide references. My partners been working for a year and been between lots of uni accommodations.

EDIT pt 2: Me and my partner already know the consequences of breaking up etc, we've lived together for 2, going on 3 years and are renting a house together. We work in the same company right now too. This was all discussed 2 years ago when we originally moved in together :)