Oh op I am just so sorry. To find out he's been doing this behind your back is bad enough and traumatic as it is, but to then find out they had a pregnancy while he's been trying with you, that's just such an absolute slap in the face.
I think op you really need space from him. I actually went through very similar with my ex and I don't think I gave myself enough space and allowed myself to be tangled back in by him saying all the right things and acting devastated. Of course the same pattern just repeated.
So I think right now you're probably a little bit in survival mode and muted to the pain of it all, also because you're trapped on holiday with him and he's now making it all about him so you're not even being allowed the space to process your own emotions.
What I would do is check in to a different hotel if you can. Or see if you can book an earlier flight home, or maybe can a friend fly out to meet you there so you aren't alone? I think what he's done is genuinely unforgivable stuff and I think you need to create the safety for yourself to actually process the scale of the betrayal. Do any of your friends have spare keys? Could someone go in and pack his stuff while you're away and store it for him to collect so you can at least go home to privacy without him and know that job is done?
I contacted a solicitor immediately because i also felt very numb and practical but in all honesty I then crashed a while later and couldn't deal with the things I needed to do to move it along so you don't actually need to do that immediately. What you need to do is kick him out of your space and protect yourself from him initially to let yourself feel some feelings while being supported by people who care about you.
He'll have a huge reaction of course, this is all part of it. But op he's not sorry he did it, he's sorry he got caught out and will now need to face the consequences he knew were coming if he got found out. And it is not your job to fix that for him.