Ok. This happenes to me. Minus dh having an affair (as far as i know he hasnt).
I got a new job, new friends, started having the odd night out etc. I became happy.
I had spent the 4 years, previous, working with dh at our business. Everything revolved around the business and dh. I went back to work to have something for me.
It did not go down well with dh. He was going through my pockets, phone, facebook. There was drama all the time. If he text and i didnt call back immeadiately, he thought i was ignoring him. He hated that i became stronger and wouldn't take his shit and was independent. I got told 'you have changed' and 'your arent the same person'.
In the end i told him that actually i am the same person. I am just more vocal about what i want and need. Dh began clinging on, smothering. Eventually i gave him an ultimatum. He got help or he left.
He had a lot of counselling and we had some joint and it really helped. It was a long road and (imo) only worked because dh realised and accepted he was being a dick, he was being controlling and he was being EA. He accepted it was him and not my fault at all.
Dhs insecurity comes from him not feeling like he is attractive enough for me. I think he is gorgeous. But i dont like how i look so get it doesnt matter what others think.
A year down the line after counselling finished he still has an appointment every 3 months and our marriage is better than ever. He has really made an effort and is incredibly supportive of me.
I am not saying this to tell you to stay in your marriage, that it will definitely get better etc. I am telling you it because, like me, its not you. Its him. Your dhs insecurities sound like they come from his affair. He did it. Now your life doesnt revolve around him, he thinks you might do the same. He doesnt want to see you stronger, have an opinion. Because your opinion might be that you dont want/need him.
My dh now says its so much better knowing i am in the marriage because i want to be. Not because i feel i have to be. But at one point, that scared him.
Your dh is being selfish. He is worries you will cheat, leave him. He wants to be in complete control and your world to revolve around him. Eventually his behaviour will end your marriage.