My (26F) Boyfriend (32M) started sleeping on top of his phone

I (26F) have been with my boyfriend (32M) for 3 years and we have lived together almost the entirety of our relationship. I have caught him in lies before so our trust already isn't solid but he's never cheated or been unfaithful, or at least that I know of.

For the last few months, at least since October, I've noticed that he is a lot more possessive over his phone. I've always been allowed to use it but lately he just doesn't leave a room without it anymore AND he sleeps on top of it. One of the ways I caught him in a lie was by picking up his phone while he was in the shower to search for a message from his family re plans we had with them. As soon as I opened his phone it was open on a message from a girl, obviously responding to something previously said, but there were no other messages. So I discovered that he had been talking to her but deleting their messages. I was able to get copies of the messages from the girl and he had been talking to, turns out he was loaning her money and keeping it from me. This instance was after I found messages with another girl in his archived messages folder. So obviously, he's escalated his ways of hiding things from me already in the past, going from just muting notifications and archiving messages to actually deleting them.

After confronting him about finding the messages while he was in the shower I noticed that instead of putting his phone on the counter like usually, now he would leave his phone in his pants pocket and place the pants behind the door, tucked far back into the corner when showering. I found this VERY odd and when I asked about it he claims there is no reason and that it's subconscious.

I finally asked him about sleeping on top of his phone also, and he literally only gave me one answer, "because I want to". I have noticed in the middle of the night if he wakes up he'll feel around making sure his phone is still underneath of his body. Also I've noticed that if I get out of bed in the middle of the night, he will also wake up and again feel to make sure that his phone is underneath of him. I let it go for as long as I can but I can't shake the feeling that he's hiding something far worse and more devastating than he ever has before.

I lie in bed at night debating whether or not to just explain all of this to him, tell him I feel uneasy, and that these actions lead me to believe he's hiding something or if I should try and sneak it out from under him in the night. That option gives me anxiety though, it makes me feel like I'm doing something wrong that I* don't want to be caught doing and also, I don't think I could get away with it because of how aware he is of keeping it underneath of him.

So basically what is the best option communicating my feelings and concerns straight out and telling him I think he's hiding something, or investigating while he's sleeping (which makes me feel guilty!) OR is the fact that I'm even debating all of this just a sign that the trust is broken and it's not coming back?