According to Planet's Doglopedia, there are 33 breeds that are commonly known to be gentle, and not prone to jealousy issues. I'll just list the ones that are small to medium sized.
1. American Cocker Spaniel ( A couple of my friends who have Cocker Spaniels have kids and grand kids visit them often because they're cuddly and loving.
2. Basset Hound ( because they're very laid back).
3. Beagle
4. Bichon Frise
5. Boston Terrier
6. Bulldogs (but sometimes they can be persistent without early training)
7. Border Collie
8. Pug
9. Standard Poodle (not the small ones)
10. Springer Spaniel
I hope this helps. If you're willing to adopt, try to find a shelter near you and ask around for dogs that can fit your lifestyle. Rescuers are very capable of helping families find dogs suitable for them.