How lovely and something to look forward to.
My first thought was something recommended to me on here for at home but which also adapts to overseas plugs
https://www.amazon.co.uk/gp/aw/d/B07QMVB2WK?psc=1&ref=ppxpoppmobbbasin_title
Generally speaking as someone who in the past has travelled/holidayed a lot I would say re packing:
Documents
IT/tech - have this on packing list mainly so you don't forget charging cables! Or earphones! So include all the "peripherals" on your list.
Meds - check the regs if any are narcotic or otherwise likely to be "controlled" I'm on strong painklllers which i need a letter for. Also CONTRACEPTION!
Jewellery - don't take anything precious you'd hate to lose. Basic studs that you can keep in without faff and still feel "groomed", rest as per personal preference
Make up - I have a basic "kit" that's neutral colour wise and so goes with any outfit, multi use products are good too
Toiletries - I have allergies so need to take my regular products so I do use the travel bottles. If I didn't have allergies I'd just do as pp and buy cheap when there and dispose of before coming home. So I take "my" shower gel, shampoo, conditioner, body lotion, wipes and deodorant as they're the ones I have issues with. Toothpaste, mouthwash, floss, I get there. Sun cream - again I have sensitive skin so I take loads of f50, Sanpro again I take my own but most places have the most popular brands/types there
1st aid kit - kinda depends on where you're travelling to but assuming a fairly good country medically speaking then just the basics: plasters and dressings in assorted sizes, tweezers, nail scissors, essential oils (I take lavender - helps pretty much everything! Headaches, burns & scalds inc sunburn, cuts & grazes..., tea tree - bites and stings, antibiotic/antiseptic for wound cleaning & insect repellent, peppermint - upset stomachs, headaches, stuffy noses), aloe gel - fantastic for sunburn and cuts and grazes especially if mixed with a few drops lavender oil, crepe bandages and safety pins,
Clothes
Wear warmer/bulkier clothes (and shoes) on the plane, layer up so you've more space in suitcase, I generally wear a vest, tee, AND a cardigan or light jacket on the plane, if you do feel warm it's easy enough to tie cardi/jacket around your waist. Jeans, trainers & socks.
Other than that assuming a "normal" beach holiday I would recommend:
3 swimsuits/bikinis minimum - you'll be practically living in these so you'll want 1 to wear, 1 drying. 1 in "laundry" as it were
I sleep nude on holiday but for those who don't wish to - light pjs or nightie or tee whichever you prefer, take a few as you sweat more at night
3 vests
3 tees
3 pairs shorts
Couple of dresses/skirts for "fancy"
10 pairs underwear - save yourself the grim task of hand washing undies and have enough spare for sweaty/period/discharge days
7 bras - i wear the crop top style ones due to disability but again it's a faff handwashing more than strictly necessary
Remember you're wearing stuff on plane too
Shoes
Remember you're wearing trainers on the plane
I'm not a fan of packing heels as they take up too much space/weight and even in a supposedly separate section they can end up causing damage to clothes - but it's personal preference, if you do take then I would say take 1 neutral pair
Flip flops - again you'll live in these probably so take a few pairs. I tend to take a couple of "plain" ones and 1 or 2 "fancy" ones they come in so many great designs now
1 additional pair of trainers if you think you'll wear them.
2/3 scarves/sarong type deals - they take up so little space and are so versatile, great for covering up if you feel you're burning or adding a little warmth of an evening as a wrap or even turning a swimsuit into a "dress", they're also handy to use to create an extra "pillow" if the ones in the hotel are insufficient or go flat in the night! Even as a bag (knot the corners).
Luggage wise I would say have a rucksack style bag for hand luggage which you can then use as a beach bag on holiday - remember to check dimensions for your airline and carry on restrictions.
I like to have in my hand luggage:.
Basic toiletries, meds, basic make up, tech/IT & chargers etc, purse/phone/keys of course, travel docs, 1 each vest, pants, shorts - just in case load luggage goes astray!
Load luggage - I manage fine for both dd and I with a standard sized suitcase. As you're travelling with partner if you're taking 2 cases I'd have it you both have luggage in each case - again in case 1 goes astray.