Boyfriend sent direct message to an Instagram model

Sorry in advance if My English bothers you. I thought this might be the best forum for me as we are international couple. We have been in relationship for about 9 months. We've had so many conflicts but always ended up being together as we love each other so much. But I coincidently found out that he sent a direct message to an instagram model. He said that it wasn't anything sexual or flirting but I feel a bit doubtful. When we started our relationship, he followed over 7000 Instagram models. I tried to understand him as he intended to make his account a hit. But I couldn't have remained calm when he sometimes made critique about my makeup, style, and even parts of my physique (I'm not perfect but I'm very much content with myself). It took me 5 months to persuade him not to do that. He finally stopped doing that and he even unfollowed all those Insta models by only 60 male models. He now seems to realize what is important to him after breaking up with exes with this kind of problem and taking me 5 months. Anyways, he showed me the message and it was truly nothing fishy but a question whether she picked up the cat from the street and decided to raise it. He was curious about the whereabouts the cat we used to see from time to time but which suddenly disappeared. He said that the cat looked exactly the same with the cat we saw so that he asked her through DM. This was during 4-month-period of our relationship and I know he liked and commented on Instagram models until 1 month of our relationship. Maybe I'm overreacting or my self-esteem is too low to see it for what it is. But I wonder whether it should be done in a way of DMing to her. Of course he was really concerned about the cat (me too) but still... What do you guys think?Oh and he posts my pictures quite often but there wasn't then.