P.S.
Wow, I can think of better things I can do for an hour and a half at bedtime. Its time to wean him mama!
Keep the door open but put up a babygate so he can still see out. Set a timer and tell him when the timer goes off, you are outta there, no ifs, ands or buts. If he protests, tell him the next day DURING THE DAY (not right before bed) that its time he learns to sleep on his own. Tellhim once you leave, he has a choice of what can happen next with you standing at the door...and then give him some choices like hug him (once) over the babygate, blow him kisses from the door, wave, etc.
Every few nights or once a week, shave a minute or two off the timer and soon he'll be used to having you in there for only 5-10 mins.