I've been with my DP for 4 years and we have 2 DDs. I was sorting the washing out earlier so I had brought the washing basket downstairs and my DD (nearly 3) ran off with it as she usually does. Anyway, I carried on sorting the washing out and then sorted her dinner, whilst she was eating I tidied up the living room and found a pair of women's knickers pushed onto my younger DDs playmat. They weren't there before so my DD must have found them somewhere (unfortunately she is speech delayed so I can't ask her where she found them). They are definitely not mine so I have no clue where they came from. Although I have no reason to suspect my DP has ever cheated, my mind automatically jumped straight to the worst. The washing basket was second hand when we got it so I really want to believe that they were hidden in the lining and were the previous owners, but I can't stop thinking the worst. So, I guess my question is, what do I do?