Feel like I'm the bad guy, no matter what I do.

Am I being unreasonable here?

My partner is best man for his mate's wedding in just 3weeks. Friend hasn't even sent or given partner an invite. They've also expected partner to have free use of my car whenever so he could try on clothing, and then to attend the wedding which is 5hrs away and partner will be gone 2nights (they've organised and paid for his accommodation).

Now, when they first had a rough idea of their wedding date, partner and I were separated (pretty sure partner is autistic 'cause his communication is even worse than mine, which has caused a lot of issues for us).

By the time friend had decided on a date, or at least told partner, we were back together and trying to work on things, which this friend knew.

They have not invited my son and I, but have expected me to go out of my way for their wedding.

Not only am I really hurt by being excluded again (it's been a pattern with partner's friends for almost 7yrs and partner just sits by and says nothing), but I'm incredibly angry at the expectation that partner can just take my car whenever these friends want him to for THEIR wedding, which I'm not even invited to.

My psychologist said straight away that they're being rude and, while she didn't say anything about partner, she certainly seemed to be very appalled by his just sitting by and saying nothing. But partner has no issue with any of this and just keeps falling back on "we were separated when they started organising it".

I honestly have no idea what to think anymore. Am I being unreasonable in expecting partner to say something?

Also, since typing all this up I've found out that the friend deliberately didn't invite me. Everyone else has received their invitations and this friend has removed partner's choice as to whether he wants a plus one.
They also paid for and organised partner's accommodation for two nights without ever speaking to him about it, they've just made arrangements and expected that he'll be fine with it.
They've also since made travel arrangements as my car isn't even driveable now, but if it were I've made it very clear to partner that he will absolutely not have use of it.

I'm now at a point where I don't want partner to attend but if I ask him not to go then I'm doing exactly what an ex friend of his claims I've done (I haven't, I've repeatedly tried to get partner to organise things but he just won't)- keeping him from his friends. But it also feels like his friends are pushing me into this corner where I'm the bad guy, no matter what.