Consider how your husband would feel if he read every conversation you had with this guy. Do you hide the conversations if your husband walks by or looks over at your screen? How would he feel to see it all? If the answer is hurt and betrayed, even slightly, you need to end this friendship. Obviously he will not respect your boundaries. However, if you cannot cut off this "friendship" because you value it too much, then perhaps marriage is not for you. This is parasitic and it will only worsen.
You have to make a choice, like it or not. Do you value the friendship here, or your marriage? Which is more important? One of them is more important to you, and I really hope it's the marriage you committed to. If it is, then you need to stop talking to him. Don't try to tone it down - it's already way past that phase. It will never tone down. It can only be cut off completely. I've seen this before. So make a decision and understand the consequences of a wrong decision here WILL be huge.