Top table for divorced parents

I’m getting married soon and am having a dilemma over the top table. My h2b’s parents are divorced, his dad remarried but his mum is single. It is not amicable, and his dad is unlikely to come if he’s not sat with his wife and we want to include her but it leaves an odd number on the top table. Should we just have an odd number or should we leave someone like the MOH off the table? Would that be strange to just have the best man and not the MOH there? Any suggestions would greatly reduce my stress… this is the only thing stressing me about the whole wedding!