I feel for you but there is more to this story

Just because you're gay doesn't mean you can't be banging your brother's wife out of spite. They say, "Love conquers all." Spite says, "Hold My Beer."

And now you can press charges for assault, and request money for pain and suffering. That condition for the will is actually unenforceable, as you can't use the law as a means to get someone else to break the law.

That's sad that he would make that up for kicks. Did the wife you did not have an affair with back you up?

Assuming this is true, which is highly unlikely since most wills are drafted or reviewed by a lawyer and must have witnesses of execution in order to be probated, you need to challenge this stat. A contract, which is part of what a will is, is immediately invalid if a required provision is illegal. Committing assault most definitely falls under that definition. Anyone tasked with "reading" the will should already know this as it's one of the fundamental basics of contract law. You have grounds not only for having the will thrown out, but for a hefty lawsuit against anyone involved in the probate and handling of the estate.

that will is definitely illegal, you could get a lawyer to dispute it and sue for what is reasonably due to you. hell testify you're gay and you could probably get a judge to agree to split everything with you!