We have this neighbor down the street from us great family. The wife has watched the kids for us here and there during the summer and we have watched their's. Our children are good friend's with their children. My question is our children and their children were invited to a mutual b-day/halloween party last saturday. Well, the parents of the birthday child last minute asked if we would like to come too for a little while we accepted. They also asked the neighbors down the street the husband didnt come but, the wife did. I got there before my DH and said hi to the neighbor tried to talk to her and she was very aloof and stand offish basically one word responses. So I said oh well she must have had a bad day. Well, when my DH got there she was falling all over herself to talk to him!!! She was really throwing it at him!?! Long story short my DH didnt stay long we had planned earlier in the day to have a fire in the fire pit on the patio because it was just a perfect fall day and the evening was crisp. So he went home to get that started I stayed at the party a little while longer. About 5 minutes after he left I noticed that the neighbor is gone! So I excused my self from the party and went home too. From the time he left to the time I got home about 10 minutes had passed she was at my house on my patio with my DH and my youngest DS! She didnt realize I was there yet and was still beign flirtatious and giggling acting like a school girl. When I appeared her demeanor completely changed and she said "oh, your here I thought you were staying longer at the party." I just said no my back is bothering me I wanted to come home. (I am 6 months pregnant) And she said well, ok I guess I am going to go home. and she gave my DH this look almost like "please say stay" He just said ok bye have a nice night tell **** (her hubby) we said hello. She kinda huffed and left. Now I know that my DH would not in a million years cheat on me he did not even notice her flirty attitude with him and how she was towards me. I hate to say it but he is to dense when it comes to things like this. I have not said a word to him about it but mentioned it to my SIL and BF and they were both shocked they both agree with me that she was flirting with him. The neighbor has been complaining about her hubby for a few months now and about 2 weeks ago she got really upset when she found out that my DH brings me roses every friday and will bring me little gifts out of the blue. So I dont know if it is jealousy or if she really has an attraction to my DH. I hope It is nothing I dont want to feel uncomfortable around her our kids are friends we have had BBQ's together and gone places together.(both family's) I am upset more because I have had a lot of stress in my life for 6 months now between my dad dying and having problems with this pregnancy and she knows all this. Like I said my DH would never ever cheat but do I have to worry now everytime we see her that she is going to be flirting with him and falling all over him??
I dont know what to do? Or should I just let it go? 
I dont know what to do? Or should I just let it go? 
Do you think I should mention it to my DH though? I didnt because I thought it would make him uncomfortable.