I think he still is in love with his ex-wife. What do you think?

My husband and I have been married for two years now. My husband has a previous relationship with a woman I have known for a long time. I didn't break up their marriage, but he and I started hanging out when they were separated. Now we are married. They had a son from a previous marriage. Their son is still pretty young, and they communicate still. I went with him to drop off his son at her house one day. Usually, I stay inside the car because it's hella awkward. Two cars were in her driveway, and he became a little curious. When dropping him off, he came back a little tense. I tried asking him about the problem, but he insisted it was nothing. When we got back, I had the urge to check his phone. I never looked for things but was adamant that something was wrong. I went through their messages and saw a considerable paragraph he wrote to her explaining why he doesn't want another man around his child. It seemed more of "I don't want another man touching you or fucking you" rather than an "I don't want another man around my child." type of paragraph. I talked to my friends about it to ensure I wasn't overreacting. Why would he be upset that another man is around his child if she isn't upset that another is around her child? Last week, their son had a birthday party, and we went along too. I observed my husband's behavior towards her and her new man. He seemed overprotective of her, and he appeared to be competing. I felt hurt, but I'm not sure. Am I overreacting?

I think he still is in love with his ex-wife. What do you think?
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