Tami: This is a common problem in relationships. It goes back to the old saying "A once-scalded dog thinks twice." He has come to associate women with betrayal and being hurt. He may not even be conscious of this.
Did you know that if you remove an electric fence, the animals will continue to avoid that spot? They've come to associate it with pain. that's what's happening with him. He's associating becoming close to a woman with being taken advantage of. Imagine if your car occasionally gave you a violent shock when you tried to start it. You would soon be very reluctant to start it and probably tense up when you did so.
One thing you can do is help him become conscious of this. Have an explicit talk with him. Say directly, "I know you've been hurt, but I'm not these other girls." Then show him that he can absolutely trust you. Always keep your word and be truthful with him. Show him that you care about more than his money. Ask him just to hold you and enjoy simple pleasures with you. You may have to get him to talk about how these other girls took advantage of him. He may even need counseling to put this behind him.
The key is to help him form new associations. To associate you with emotional safety and trust. It will take him a while, but you can do it. The fact that you've sent this post tells me you're a sincere person. He's a lucky guy and I hope you can help him get past these negative experiences with women.