I need help with my insecurity anyone?

So I have been Married 5 years. But my husband and I are high school sweet hearts we have two kids and our last one on the way. We've been through it all, cheating, lieing, jealousy. Thankfully all in high school. Nothing sense being married thank god. That being said because of these "experiences" we have made a deal with one another that we will NOT have friends of the opposite sex and we would not have #s of the opposite sex. (So please those of you who are going to say we can have whatever friends we want, just remember my husband and I are not like that) so that being said, I still am over the top worried about EVERYTHING I don't know why! There's something wrong with me. I'm so insecure :/ and I don't know how to fix it. I have gained 40 pounds through all my pregnancies and I got to the gym twice a week but I have hashimotos so it rarely helps. And our kids refuse to sleep in their beds so they are sleeping with us and we used to go to the front room to have "intimate time" but lately he doesn't seam interested. I even sent him naughty pictures yesterday hoping it would spice things up when he got home but nope nothing. And then today he was talking to me on the phone and made a comment about getting food for people at work and he mentioned a girl at his work as a "close friend" his words not mine. I immediately started panicking and didn't say anything to him. He just moved on like nothing but I can't stop thinking about it. I know I'm overreacting I know I shouldn't see it as a big deal but I can't change the way I feel. Maybe it's because I stay home all day everyday and he is around adults of both sexes all day everyday so I feel threatened. I don't know. How do I stop it? How do I fix getting worked up over such stupid things? Sorry this is so long. Thanks for reading.