I don't think it's inappropriate to compliment YOU on your looks, but I do think it's sexist to somehow compliment your husband, since he has no role in making you beautiful (assuming he didn't do your hair, makeup or outfit). It's as if your husband was to be complimented on acquiring you!
And I understand that your husband felt awkward and was taken aback, but his response should not have been "Thanks" (because he has nothing to do with you being beautiful) but rather it should have been "I think so too" or "I agree."
Different people have different traditions and customs, some are free with their compliments, and I don't think there's anything particularly forward about it. Julie was told that you had 2 beautiful children, so she certainly couldn't reply, "Really?" or "How interesting", so she had to say that you were beautiful too. And perhaps she truly thought so. Accept the compliment rather than put yourself down and imagine that women who've had 2 kids can't be lovely.
If excessive compliments continue, you can say, "Oh dear, I'm getting all red. Can we talk about something else?" and then have another subject ready! Unless this couple should persist and talk about wife swapping (in which case you shut it down and say "I'm not comfortable with this line of questioning at all"), I think you're in the clear. My guess is, they are complimentary people who find the good in others. You may find it's, in fact, very pleasant to be around positive people.