Am I in the wrong

My husband has three kids with one other woman. He told me they were meeting at a Walmart internet here and where she lives which is what they always do. His daughter told me they met at her moms house (his ex) and I asked him why he had to lie. We have court papers saying we get them every other weekend and he says he wouldn’t get the kids if he didn’t go to her house to get them. Here is my frustration. He legit told me he was at Walmart and that he got the kids cause her boyfriend dropped them off and that he was headed home. This butt went all the way to her house lied to me and came home. Like nothing ever happened. I explained to him how I was upset at that it was wrong to lie to me and he said he doesn’t think he was in the wrong and he won’t apologize. Am I wrong to be mad and hateful and not trust him? Legit? We have been married almost 6 months and have a daughter of our own.

Edit:

I don’t know how long he was there. Just the fact that he thinks he’s in the right for lying kills me. What would you guys do in this situation?