Early on my wife wasn't that much into swallowing. It was then that I made a point of tasting my own cum. I then progressed to licking it from her boobs and eating her cream pies. Actually got to love it, but more importantly, I was able to show her that it isn't bad, dirty or something she should avoid.
Basically, I showed her that I wouldn't expect her to eat anything that I wouldn't eat...
Now when I cum on her boobs, we both lick it off and when I leave her a cream pie, but she hasn't cum yet, she will fuck herself with a dildo for a bit then suck the dildo clean as I eat her to a cum
Good stuff comes from eating your own cum!