I was with my DP for six years, he was my DP despite not living together.
He made it clear to his family that this was the case, so I was treated as family, not as a guest who needed entertaining.
Likewise I have treated my adult DDs Partners, the same.
He is a Boyfriend and one that would see his financially struggling (to put it mildly) GF, out of pocket, when he could change things, by assuring his parents that the OP does not need the status of "guest".
His parents are in their 70's, I'm late 40's, my GM, my Mum, I and probably nearly all of you, will be having to still work full time, if there is work.
He should of, at least, reimbursed the OP.
OP, if you were to move in with him, as a Partner, then he could of guaranteed the rent, very different if he described you to his LL as a co-tenant, or lodger.
"There's something bothering me/not sitting right" (your phrase), because there isn't.
Ignoring and advising him until you feel a bit better, isn't the way to handle this,
Is this and not moving in together the only "blibs" that you have honestly had?