You don't have to feel ashamed about your thoughts, to start. They're just thoughts and we can't help where our mind goes. But what you can help is your actions, and when you say you "can't" stop texting the other man who wants to have sex with you, you're just making excuses for your behavior. It's not that you can't stop, it's that you don't want to stop.
There's nothing inherently wrong, I don't think, with wanting a deep sexual connection with your husband, but it's not something that just happens. Why don't you talk to him about the fact that you don't orgasm? Why not tell him how disconnected you feel? It would destroy him if he knew how unhappy you were? Nope, it probably wouldn't. What's more likely to destroy him is you cheating on him with a "friend" of yours, without him even knowing anything is wrong. If you both don't discuss what's going on, how is your relationship supposed to get better?
If what you want is to have sex with other people, then you owe your husband honesty. Have you ever talked about having an open relationship with him? Would you be willing to lose the life you've created for more "experience"? I think it's easy when you're in a relationship, with all the ups and downs, to focus on how humdrum it is. What have you done to add passion to your marriage? What could your husband do? Why not just tell him about your needs?
If this is just a "rough patch", you need to stop texting this other man, put your effort into your husband, and at least allow him to try to be the passionate man you want. You need to be honest with him about your expectations of married sex life, and with yourself about what you really want. If however you do want to have sex with other people, at least allow your husband the dignity of not being a chump and tell him that you want to break up. If he's otherwise perfect for you and a generally kind person, the least you can do is free him to find someone who can appreciate him more fully.
I wish you the best of luck. Stuff like this can be really confusing, but with communication and effort, you can make the right decision for yourself and a fair one for your relationship.