My name on deed of husbands house and he wants to refinance. Important question

Here's the situation. My husband owned the home we live in prior to marriage. I had him put my name on the deed as part of a stipulation in signing a prenup. He has two kids from two different relationships. I wanted to protect myself in that i would get the house if something happens to him. So, he wants to refinance the mortgage. SInce my name is on the deed, i have to sign the mortgage also. I don't think he realizes this.
He bought the house for a whole lot less than it is valued at today. He wants to take out a couple of hundred thousand dollars extra and so we would have a bigger mortgage. I don't work, and his income is considered marital income which is what is applied towards the mortgage. He wants to take this extra money and pay off some margin debt in his "Personal" brokerage account. He also wants to do some other things with it that are in "HIS" interest. Can he do this legally since my name is on the "New" mortgage? Let's say he takes a lump some and invests it in an account with his name on it only. Let's also say that this investment gives him a high return. Since marital income is paying off this new mortgage, wouldn't the new investment account be mine as well as the return on it. He also owns his company with a partner. They are trying to raise cash. He was talking about taking the money from the "loan/new mortgage" and putting it into his company. Wouldn't I technically own a part of this company now? I believe the answer is yes to all of these questions.
Thanks.

[HomeGuru]

Tell him no, you will not agree to refinance.