Worried for my marriage

Over the last eight years of my twenty five year marriage has reached the point we only make love around six times a year. No other intimacy such as kissing or cuddling. We hold hands and give each other a peck on the lips. I have tried to talk to her but I get the feeling she is not listening or is not interested. I adore her but I am worried she is having an affair though I have nothing to suggest it. When we go to bed she will roll over and go on her phone. She says you can cuddle me. If I try anything she says it late or kissing leads to other things though she will be on her phone for an hour or so. In the morning when we have to be up for work she is all loving and touchy. I think this because she knows we cannot do anything. I am at the point now were I am thinking life is short and this is not fair on me. Any advice. Thanx