Ex boyfriend gave me a hickey?

Here's what's confusing me:
He still cuddles me at night (my head on his chest with his arms on me) and asks to do that every night
Pays for dinner when we go out/order takeout
Wants to be in the same room with me (and if we're not, he'll come into whatever room I'm in) and will move to be closer to me
The other night, texted me when he got off work and asked if I wanted to go to this restaurant (it's a nice restaurant with low lighting and candles on the table.. a place we used to go on date nights and said he was excited for our fun day..)
He calls us friends but he always said that he only goes to super casual fast food kind of places with platonic girl friends.
Gets super angry/jealous when he thinks I'm interested in a guy. Like REALLY angry.
Now I know this isn't smart and it's only happened a few times the past week or so, but we've started having sex again. His sex drive is back and he's in the mood all the time (which was a factor in why we'd been fighting a lot before. I didn't feel attractive or desired) He kisses my neck and cheek during which is something he considered romantic before.
A guy friend of mine who has a crush on me showed up at the apartment yesterday and wanted to take me out on a date and my ex went out and told him to get out of here and some other stuff. Then my friend texted me asking if he could talk to me in the parking lot and I agreed, and my ex watched from the porch to make sure I was ok (he doesn't like or trust my guy friend).
So last night, we had sex and he seemed more aggressive than usual and seemed really dominant
(this sounds stupid but it felt like he was trying to prove he was like the alpha male and that I was his)
and he was biting my neck and giving me hickies (he always bites but something was different)
and I asked if he was marking/branding me and he said yes. Why would he do that if he didn't want me to be his? He then said I should send that guy friend a picture because "it wouldn't hurt to send it"

Updates
+1 y
He was struggling with moderate depression which was making him have no motivation, wanting to ignore the world, no sex drive, self loathing, etc. and we were fighting a lot because of it
He said he needed to take at least a year to work on himself before dating again because he can't be happy with someone else til he's happy with himself.
The past couple weeks, his depression has seemed almost non existent with him being happy a lot again and wanting us to spend a lot of time together
Updates
+1 y
We're still living together while I wait for a new apartment to open up.
He'd told me a couple weeks ago that the reason he didn't seem as upset as me was because he doesn't have time to be sad and that he moved on. Then about a week ago, admitted he was lying about that and that his heart was torn but that he's hiding it (he's super out of touch with his emotions)
He'll hug me when he leaves for work but doesn't kiss me or anything. He only kisses me during sex.
Ex boyfriend gave me a hickey?
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