How its possible one married women's l *** out without husband?

my wife gone to work,she came late when i picked her from the office to home,she changed her dress after that i saw her pantie laying in the floor,i take all to put in the basket,that time i saw her pantie under wet with Oliy,then she came up i asked her what is this in your pantie and she said nothing that is my l *** [lubricant],i asked her how its came out and she told me that i came with you that is why!!......so i was thinking how it is possible l *** discharged with out her husband do nothing,otherwise she had with some one in her office with out my knowledge or what?.Because she is very free type with other man in her working place!, one man in her office recommending promotion for her, i do not know how is this man?!!!....and she has his cell number which i found it in cell phone!!!....?.....!!!! how i can get answer for this.....?....!! tell me!..?