Help me sorry it's so long.

Dillon
So i have been with my husband for a little over for years now. We just got married in March. He's a little (13 years) older than me. We have four children together, we don't have sex often, in the beginning we did but he drank alot like borderline alcoholic​. Then before we moved in together I have him an ultimatum quit drinking or we are done, he quit hadn't touched alcohol since. Seriously greatest husband and father to our kids. But it really really bothers me that we barely have sex. I was using his phone to send the pictures he had taken of our kids to my phone so I had them also and I found porn. Four different videos saved to his phone. He never used to watch porn. And here lately or sex life has slowed down even more and I'm guessing it's because he's watching porn. Should I be mad or how an I even supposed to react. I mean if he would have watched porn before I wouldn't care but it's just all of a sudden he's rejecting sex with me and watching porn when I'm not around... Am I making something out of nothing?