Divorced parents during ceremony

I know many people have divorced parents. I am worried about my ceremony so I am looking for advice. My mother and father don’t talk anymore but they can be civil. My brother recently got married and they both sat in the front row next to each other with their significant others with no problem. The difference at my wedding is that my father will be walking me down the aisle. My mom will have her boyfriend to walk her down (they’ve been together for 15 years so he’s part of the family). My father has been with his significant other for maybe 4 years so it is a serious relationship. I want her to be able to sit next to him during the ceremony as they are a unit. Should she walk down the aisle like our grandparents and parents are right before the bridal party? Who would she walk with? We spend time together when I see my father and I really like her but I wouldn’t say we are super close. I don’t want to make her uncomfortable either.