Does it help to say that most of us have been exactly where you are right now? Does it help to say that 3 different times I have told my girls that we are getting a divorce? but then we change our mind?
Probably not.
I don't think there is anything wrong with telling him that you noticed the pads were gone, and say that you didn't realize someone else was going on the trip. See what he says. I don't tell you this because it will do you any good to know there is officially another woman, but this would be your opportunity to state your boundry that she is not to come near your child. I did. He totally understood. My girls are 12 and 10 though and would KILL thier dad if he brought her around them. Your baby is too little, but she doesn't need to see her dad with another woman which would in the least confuse her. You don't have control over him, but you can set boundries with your child. At least I did. I was very calm, not angry at all. Just put it that we had to be very careful with the kids and make sure we did this right. My H has been in total agreement. Some LBS are not so lucky.
I would suggest that you reach out to PEI - she is a vet and she is dealing with her H introducing her young children to the OW - BUT they have discussed this together. Sounds like your H is doing it behind your back.
Try to relax and remember that he is crazy as a loon right now. THIS MAN IS THE ONE YOU DON'T KNOW - NOT YOUR SANE LOVING H OF 14 YEARS. Set your boundry and try not to do something you might regret later.
Wish I could be there to give you a big (((hug))). Hang in there.
TAMF m:41 xh:41 T: 20 M: 15 D: 16 D: 14 Bomb dropped: 7/3/10 separated: 7/15/10 H moved in to new apt. with OW: 7/1/11 divorced: 8/26/12