I have to take my SO on vacations, otherwise she starts to crack up. I have a man cave that I hole up in during PMS week. During that week, I leave a full glass of wine out on the counter for her when she gets home and I disappear to the man cave and don't come out for anything. Otherwise, I just try to maximize time spent together on days off. She likes outside stuff, so we'll ride bikes or play tennis, etc.. At night she likes to cuddle in bed and watch t.v. shows so I try to be available if we're both off. If I have a night shift, I'll watch t.v. with her until I have to go in... Otherwise, she hates getting up early, so if I'm off, I'll get up and walk the dogs, get her breakfast, etc.. and that seems to score additional points. If I'm on nights, I try to do all those things when I get in, before getting in bed myself.
The vacations don't have to be anything extensive...recently we took the dogs to a cabin a few hours away and paddled in the creek, grilled out, etc.. It's relaxing but I've never understood why she has this "checklist" and frantically needs to check box "vacation" and post her obligatory instagram/Facebook posts. It seems to reset some internal circuit and we're good for a few months until it's time to checkbox another vacation.
Neither of us have or want children so that probably greatly reduces the stress. Luckily, she used to be an EM NP and although she's been in FM for a few years now, she hasn't forgotten how difficult the schedule could be so she's understanding when I'm grouchy, sleep deprived and generally unpleasant to be around after a string of nights, etc..
I'm most definitely not a big expensive jewelry/gift giving type of guy but I do a lot of "small" things and am generally pretty affectionate and that seems to go a long way with her. However, even with no gifts...the vacations add up each year. We do a big ski trip, big Caribbean trip, big hiking trip, couple dog vacation trips, etc.. each year. I think I probably spend about 20K on vacations every year. If you don’t have kids and she still needs this much attention, that is insane.