Am I Overreacting

Am I overthinking things or not?So my boyfriend and I haven't seen each other for 1 month,2 weeks and 4 days. Until today(which is Friday 7 August)Things were all good until later on today in the afternoon,when him and his friend were talking (beside me) I didn't hear his friend,but I heard him(my boyfriend) say,"I don't like her anymore.I'm joking!"I'm assuming his friends didn't hear him so he asked him what did he say then he said he said nothing. Later on today he texts me and asks,"Is it cheating if I flirt with another girl then tell her it's a joke?"I told him it'd emotionally cheating as it's the way I view it. Then he asked,"So it is?" And I just said the same thing he asked if he could do that I said it's his choice and life I shouldn't tell him what to do as I don't want to come out as controlling. He said he doesn't want to do anything that would make me sad or make me feel a certain way so he won't do it. Now,I'm thinking to myself,"Why did he want to do it in the first place?" I'm lowkey starting to doubt our relationship,now. I don't know what to do