I need to find more ways to get him to be here in the evenings so that she has to wonder
As fun as that sounds, do your best to keep the focus on you and rekindling your R -- let OW sink herself without allowing the process to take up YOUR time and energy. Simply be the better option. Be sexy, fun, clever, subtley flirty, elusive, busy, new and fresh, etc. Eff the OW.