Confession

I was looking for an address that my husband had saved in his phone and while looking for it he received a message from a woman named Carol, that said "we should get together more often...". The problem is I've never met or heard of a woman named carol, and the ... at the end of the message left to much to be desired for. I deleted it and I haven't told my husband yet. I'm so confused, I never would have believed that he would cheat on me, but after reading that text message I don't know what to think anymore. I'm scared if I try to confront him that he'll just deny anything and cover his tracks in the future. I want to find out the truth without tipping him off. If he is cheating on me he's not going to get away with it that easily. I didn't put 12 year into a marriage to end up getting stepped all over.