I appreciate your honesty in this, but my answer to you is "no where". Proper tattoos cost a shed load of money, it's painful, and in the event (not saying it's going to happen) that you guys split up, it costs shed loads to remove the tattoo. Have you thought carefully, long and hard whether you want one for yourself and not under his influence? Do you have the money by yourself to spend on this? And how would your family or your other loved ones would feel about this?
I suggest using the none-permanent, fade-away-through-time "tattoos" for yourself.
I'm a bit old-fashioned so I suggest on the right or left of your upper arm where your sleeves can cover it, or wherever that you feel comfortable that it doesn't look weird when you wear clothes or reveal it. This method costs way lesser, his name appears there and you put his name whenever you want after the "tattoo" fades away, so it's a win-win situation.