Does it take a lot of "activities" by your s/o to make you jealous?

After a few years suffering with my ex through his mad crushes on girls half his age, sneaking around and suffering through my insane jealousy I can’t take Any foolishness anymore. I’d walk out. Not proud of it and wish I were different. How about you? Are you tolerant of your s/o emailing others? Talking on the phone with them? Having coffee or worse? Or can you look the other way and laugh it off?