Waking up gasping without remembering it, especially when someone else notices, often points to a brief pause in breathing during sleep, commonly from obstructive sleep apnea. Acid reflux reaching the throat at night or an anxiety-related awakening can look similar, but the pattern you describe is most typical of a breathing-related sleep disorder.
Next Steps
A sleep study is the test that confirms this and shows how often it happens. Ask your partner to also watch for loud snoring, long pauses in breathing or choking sounds, and notice if you wake up tired or with morning headaches.
Health Tips
Please see a physician or a sleep specialist soon, since untreated sleep apnea over time can raise your blood pressure and strain your heart.