Heading toward affair- what to do?

[hopeOK]

Help!

Well... Didn't hold back. Asked him- where all did you go today? He looked a bit off. Then he said- ummmm... What is that store called? The grocery store? I told him the name. He said- yeah, I went there. I said, where else did you go. He was silent. For too long. I said- think fast, come up with something! You went to work... Where else? He finally came up with a restaurant. I asked him where that was... Turns out only 6 minutes away. I said- that is a lie. We can talk more about this when you are ready to tell the truth. Then I walked away.

He is sleeping in S6 room so I know he is avoiding any further conversation about it.

What in the world am I going to do now? I have no hardcore evidence, I just know he went somewhere & lied about where. Pretty damning but.... Nothing definite. Now we have this vacation coming up (which is paid for) & I've got to figure out if I stick with the plan from before when I knew they were just talking as friends or change it. I do not know how I am going to get any more hard core evidence... He has not been texting/emailing by text to talk on the car this week at all.