What Causes Foul Smell From Vagina After Sex?

Hi Doc,
Greetings! Merrry Christmas.
I am a 42 years old mother of three. My husband suffered a stroke bout three years ago and for almost a year and 4 mos I haven't have no sex at all. However, bout middle of 2009, my former boyfriend ask me if he could be a replacement in the absence of my husband particularly sex. So I accepted him because I also love him. So I had an affair with him and up to now. We frequently see each other and we had a very good love making. I really feel the love that he is giving to me particularly in our love making. I know that this guy never touches any women because i always check his whereabouts and he is quite a religious person to get another partner. My worry is when we had sexual acts, after that, there is a foul ador coming out from my vagina and it is so embarrasing to my part. Maybe you can help me sold my problem. I don't know why. Well, as I told you that I am a ligated women. Is there any connection bout the foul odor and as a ligated person.
Thank you very much.