Advice please ladies!

Jackie
I'm 25 going on 26 this month with a 5 year old daughter who is my world. Just got divorced last year(my ex husband cheated on me 3 out of the 4 years we were married). After my divorce was final, I got back in touch with my daughter's birth father and well long story short we got back together. Its been about 5 months now and i cant help but feel that im not fully commited to this new relationship. See a couple of months ago, i went through his phone (bad habit from my marriage) and saw a text between him and his ex wife nothing crazy just something about a credit card but then he randomly sent her an old picture of the two of them and said she looked hot in it, granted we were already together at this point. When i confronted him, he asked how i felt and said there were things he knew he shouldnt say to other women. I kind of brushed it off at the time but now its resurfaced am i crazy bringing back paranoia from what happened in my previous marriage or is this a red flag? Thoughts ladies?