Turtle question for people who have them?

ok so i have a three toed box turtle (tourtise technically) and shes wonderful and ive had her for seven years now but shes about 10 or 11 years old though but when i got her i had a smaller living habitat for her which ive had her in since then (i hve a big outdoor one for her she likes so she gets out) but anyways yes its a female but im building her a large indoor habitat and i feel so horrible that shes alone but i havent had the room to get a second one i just think she needs a buddy but im worried that if i get another male box turtle theyll mate when i first got her she layed eggs a couple times but she hasnt in a couple years and i dont need baby turtles but im worried if i get a female there the kinda of animals that would fight with the same or that if i get a male hell be aggressive and mean to her or could i get her another very similar species of turtle that might get along (has to be around same size and care of what she is) what is the best thing to do i deperatly want to get her a friend.