Husband has low sex drive?

Lately my husband has absolutely not wanted to have sex when I try to. Unless he feels like it which is hardly ever! Even when I try to come onto him he says he has to pee or pulls away from a long kiss or just shrugs off what I'm trying to do and goes back to watching tv or being on his phone. Sometimes he'll even be aroused and kissing me and then he just stops. I've tried talking to him about it but he doesn't really act like its a huge deal. He doesn't even try to say anything like "I'm tired". Have any of you had something like this happen? What can I do? I'm getting a little frustrated...lol