Air Humping, Inexperience and Attachment vs Love

So my fiance is amazingly loving like a teenager with puppy love, however I don't know how to approach him regarding some strange things he likes doing in the bedroom. Straight to the point he likes air humping me but not having intercourse. I think it's very strange because we're engaged now and he's still preferring to hump my body and not go to my sweet spot. I feel even more uncomfortable with how he likes plopping over me one leg pinning down each of my arms with his legs leaving his Johnson flapping on my chest not my boobs but my chest... I don't understand where he gets this from I've never seen or heard about anything like this before I've had many sexual partners he has one had one sexual partner prior to me. someone please explain to me why he might like this over having regular intercourse with me. We have had conversations about not wanting to have children prior to getting married so we use protection if he ever wants to venture down to sweet spot but I'm dumbfounded about how this is enjoyable for him. I definitely think he needs more experience but he's reluctant to learn anything new, someone please help sort this matter.. help me understand why he wants to keep dangling over me.

Another issue is I am having trouble understanding if truly loves me or is just attached to me. According to his therapist he has attachment disorders and he is having major problems getting past his ex of 6 years whom he broke up with over two years ago. All I keep hearing is this is what he did with his ex and he found pleasure in the information above... is it possible he may be attached to me because he is trying to get what he used to have with ex who is now married to his ex-best friend... both of whom he met while in High School... just a few questions... might I add he proposed to me recently and I'm second guessing the decision out of fear that this is the actual reason he proposed and not because he truly loves me... any feedback would be appreciated.