I think my husband is cheating....again

My husband and I were married for almost 13 years. We divorced after I left him because I couldn't trust him after he had cheated on me with two different people. We stayed divorced for over 2 years. Now we have been remarried for almost 2 years. In that time, he has cheated on me at least twice with his ex. Well, we agreed to give it another try. He says he cut off all contact with her, but I wonder. He is a truck driver and gone all week, home o e weekends. Well, the last 3 weekends he has not asked for anything physical, not even made out. He has also been more distant lately. Am i being paranoid or do i have a right to question it. My gut tells me it's happening again.