What he heck????
Where are you getting that.
Nope, not what I said, or meant, at all.
I never said he was a child....
I said, several times, HE IS A 34 YEAR OLD ADULT....
(there, does the bolding help any)
Therefore should be conducting himself and taking responsibility for himself as an adult... not acting like a 'teenager' and sneaking a girl into his room in his mama's home while she is away.
Nobody can convince me that he truly thinks that it is Okay and that he is 'entitled' to sleep with random woman in the OP's home....
He did, after all, wait until she was gone, and has never seemed to have discussed this possible situation. It is 110% clear that he must have know that his mom would at least be a little uncomfortable.
IMHO, (and, I am entitled to my opinion) a 34 year old adult who has not found a way to become financially solvent, keep a roof over their head, even drives mama's car, etc... is simply NOT conducting themself like a mature, capable, adult.
OP, I am sorry if you don't understand why you think the relationship is odd. But, I continue to believe that if any 34 year old, male or female, whatever, lives at mama's, for free, drives her car, etc... That it is a bit 'off', and possible a codependent situation.