Unlike child support, spousal support is often very difficult (if not impossible) to modify after the divorce is final, so getting it right the first time is a must!
You're never entitled to half his trust fund. Even if you were still married to him. All you get is the opportunity to follow along with the things he buys & fun he has when he's buying things & having fun after the money from the fund comes to him. And when you leave, the stuff he bought with the trust fund stays with him... and any money left from the trust fund stays with him too. It's his trust fund, started (probably) to make certain he didn't give it all away to someone else... like a friend, girlfriend, or wife.