Don't know what to do

i just recently left my husband for my new partner (my marriage was dead for years) we now live together and he wants to marry me my marriage was a disaster we should never of gotten married but any way i met my friends brother and really liked him for months but he was with one of my friends they split up and we got talking and got together thing is a couple of months ago i caught him chatting to anther girl there was nothing sexual or anything in the messages apart from she called him gorgeous which he is, he told me it was a family member which didnt sit right with me so i just said ok n went on with life with him but then the girl who was messaging messed me out the blue and told me she wasnt family and that he shudnt lie, he has made me so happy since being with him, but then i got a awful message from his ex (my ex friend) basically trying to break us up with what he was like when he was with her ie messaging other women and so on, he keep reassuring me he wont do it to me and that am all he wants ect ect i just cant get it out my head that he is going to do the same to me but the thing is his phone goes off all the time and some times he hides it and keeps it on silent but yet when i ask for it he does give me it and yes i have checked it and there is nothing on there, anther thing tht winds me up is that hes got alot of girls on his Instagram as well i suffer with bad anxiety so i dont know if all this is just in my head or not because he really hasnt given me a reason not to trust him i just dont know what to do to get past this.

Yeah I agree with the other commenter. I'd be surprised if he doesn't end up cheating on you, or leaving for another short term fling. Assuming he hasn't cheated already. Best that can come from this situation is if you save yourself from it by leaving now. Possibly trying to patch things up with your friend if she's open to that. Otherwise just forget the whole situation and find yourself a loyal guy that doesn't trigger your anxiety.