Trying to enlarge my circle of friends with kids, met this particular one at some busy kids parties, then a few times with other families too, recently she came to mine with her kid. Husband says she gave him a clear flirty look when I wasn't around, he wasn't comfortable with this and avoided her thereafter. Never really had this issue pre-kids or after kids in 13-14years, he's never said someone tried to hit on him, amongst friends or groups of people who know we are in a relation. She's in a complicated relationship with her child's father. I'd probably describe me and husband as modest people and private about our relationship, no PDA ever either, just to give context to say that we would never flirt as banter.
How big of a red flag is this in my friendship with her? Husband suggests to just keep our meetings to parks/play places and have a more superficial friendship ( I have already stupidly overshared some things with her, to do with our children as I felt her as trustworthy and genuine).