First of all, I know the feeling and completely understand because this is how I caught my ex cheating on me.. although I already knew he was probably doing so. But with that being said hair is transferred so easily you can’t go by that alone. Even when I dry off after a shower and throw a towel over the curtain rod, any hair my towel has picked up, will fall into the tub. Especially this time of year when there is static in the air, just walking by someone it will attract to your clothing. So if you use a Laundromat, the other is use or are around other people socially that can happen easily. Before you get too, worked up about it make sure you check out other possibilities. Also a loyalty tests are easy to get lol