Is this cheating please help i'm lost at what to do!!!!!

I have been with my hubby for 10yrs & married for 4yrs on & off over the past few yrs I have caught him on chat lines/dating sites also making phone calls to sex lines....We have talked about this before & he says it means nothing & he's not talking to the same person all the time just wants someone to talk to & I have come out asked if he is having an affair he said no & I really couldn't see when this would be happening.....We have tried marriage counselling & that stopped after 2 sessions I think mainly cause I wanted to bring this issue up & he said that he doesn't need to talk to anybody cause he can work it out... But lately it's getting worse he's doing it more & also sneaking around watching porn (which is ok but I hate the lying & sneaking around bit)......Not sure what to think anymore part of me wants to go & part doesn't (we also have a 3yr).....Maybe I'm just soft & a push over for letting this happen but I don't know what to do...I'm soo lost!!!!!!