Falling apart

My boyfriend and I have lived together for two years. He has relationshipsome with several "friends" on line. They share nasty pictures of themselves and talk dirty. Sometimes he masturbates while talking to them but we only have sex every couple of months and it is short and sweet. He tell his friends that he is lonely and horny. I try to initiate sex but he just rolls over. He is supposed to meet someone for lunch tomorrow (I'm not supposed to know). Should I confront him or let him do whatever he's going to do then confront him? I know what my head says too do but my heart keeps giving 2nd chances.