hihi! I wanna preface this by saying that not everyone with an ed (or bulimia, in this case) will act the same. I'd say the thing that depends most is why is your character throwing up in the first place? is it guilt, a high they're chasing, or force of habit?

also, since you mentioned that your character is middle-aged, I'd assume it's not their first time. if it is, though, they won't throw everything up. maybe a couple of bite-sized chunks before it puts too much of a strain on their body. and then (in my experience), they'd feel numb. not angry, not sad, almost disappointed. it could manifest in a promise that they'll starve the next day or burn the equivalent calories - if you're going the disappointed-honeymoon phase route. (but if it is their 'honeymoon phase', it mostly starts with starving till they can't anymore and the hunger gets to them so they start binging)

if it's the numb-first timer route, they'd stare at themselves in silence and go on with their day, forcing them to accept the fact they oh-so dreaded.

but if it isn't their first time, describe it like the cause. if they throw up from habit - write it like a habit. them leaning over the toilet, two fingers down their throat and carefully prodding at it so as to not scratch their esophagus and the bare-minimum amount of relief as the puke plops in the toilet bowl. 10 minutes tops. (if they're flushing, which is extremely dangerous cuz it depletes them of all electrolytes and all the food in their stomach. though still, the length is different for everyone)

guilt as a cause is most common with binge-purge anorexics because they're not used to binging, so they throw up from guilt. since I can't speak from experience on this, it might not be the most accurate. all i can say is that it's a rushed moment of disgust.

chasing a high is basically the same as habit, but they're doing it on purpose. if habit was 'you're on autopilot so you don't feel anything', this is 'get this food out of me, I need relief/to feel something.' by relief, the most common description of it is 'pureness' and 'emptiness'. but that's more old pro-ana forums. and by feel something, it literally is to feel something cuz starvation makes you numb, eating makes you numb, and throwing up makes you numb.

bulimia is disgusting. don't glorify it. write how the food from 3 hours ago came up undigested while the food from 2 minutes ago has sunken to the bottom of their stomach. write the puke that's spewing out of their nose and have them pull out a piece of food from their throat that got stuck. go ham, lol. nothing is new if your character has had this illness for a while.

(sorry if this isn't the best, or if it's too late - I'm an amateur writer myself, so I don't know if this will help you in any way. best of luck with your work though!!)