In my Florida divorce case, can I use my spouse’s affair against them?

The short answer is no. Florida is a no fault state, so consequently adultery does not constitute any advantage to you in getting a divorce. However, in terms of dividing marital assets, if a spouse has wasted or spent marital assets while pursuing an affair during the marriage and before the divorce, then you may be able to recoup some of those lost funds as a result of the adultery. The answer in short form is no in terms of grounds, maybe in terms of equitable distribution.