Could My Husband be Cheating?

I believe that husband may have cheated or is on me. My husband and I got previously married to each other in our teens and remarried again 13 years later. We have been married now for 4 months and have a 16 year old son together. He has had a history of cheating in the past not only with me but with his other relationships that he has told me about. He assured me before we got remarried that he has changed and no longer is interested in other women that way because he had had his shared and would be honest with me and tell me if it came to that. During our recent courtship we had no augments but now we ague at least once a week. He and my son just relocated here (a major city) and he has now been driving concrete trucks for almost three months. Even thought he is new to the area he does drive trucks and his work schedule is very unpredictable so therefore it’s easy for him. I notice two scratches below his upper shoulder (on his back) and asked him what happen. Well he told me that he climbed on the chute or was of his truck (without a ladder) to clean his truck and slipped and fell. Well I find this hard to believe because 1) the scratches are too close together 2) the concrete truck is huge therefore every part on it on it should be huge so I don’t believe that there is anything part on the truck that it is small or close together 3) how could this suppose fall affect his back 4) if he got these scratches would it not tare through his shirt (since he was at work). I have address all of these concerns to him and he just laughs and ask me why would I ask him something like that and tells me I am over reacting and that he would show me the shirt with the tear but said that he should not have to because he would not do something like that-I am just being insecure. I think that he thinks I am stupid and trying to use reverse physicalogy. I am embarrassed to say that I took the liberty of checking all of his shirts and found no tares. I don’t want to keep asking him because I want to trust him. I don’t want to be in a relationship where I cannot trust him and have to check behind him. I don’t know if I should ask him again and to give me more inforamation and let him know that I checked behind him (by checking his all of his shirts). U so desperatley wna to to trust him and not let distrust be the bases of our marriage. For once I want a happy and stressfree relationship. Please advise. Thxs

Not so sure about my husband