I am about to meet a close female friend of my husband, for the first time.....?

my husband and i have been together for 5 years. Prior to us meeting he used to hang out (just friends) with this girl, Mel. She is now married with 4 small children. All this is ok! The issue is, when my husband travels interstate to visit Mel and her family, Mel takes my hubbie out "shopping", then "forgets her purse" so my generous husband ends up paying for her little treats!!! He feels so uncomfortable about this, and doesn't say anything! She treats him like a "rich uncle" because we don't have kids and she is part of a "struggling" family!!! She and i spoke on the phone yesterday, and she sounds nice, but when i meet this family today, i can't help feeling resentment that they treat my husband like a "sugar daddy"? He's NOT rich by the way! He works very hard, long hours! Advice please! I meet them in a few hours!!