@Renzy,
If you have been married for four months and have never had sex, then your marriage has never been consummated. A lot of cultures, even rather traditional ones, allow for an annulment based upon that.
Consider if that is what you want.
Right now, you don't have a lot of evidence of anything, and you're already snooping in his phone. But things don't look good, regardless of his reputation for fidelity. It doesn't matter much if he is faithful but does not show you affection or attention. It need not be constant, but it's a pretty safe expectation to want to be at least paid attention to during the first six months of what is supposed to be a love match.
Have a conversation with him, on the weekend and not when he has just come home from work. Whatever you are supposed to be doing - visiting people, cleaning up, whatever - put it off and have this talk.
Tell him you are unhappy. Tell him you think he needs to revisit what a marriage - particularly one that is supposed to be based on the feeling of love - is all about. Tell him that all this fatigue, at his age, makes you wonder if he is ill - and
insist that he get a medical workup even if he claims he is fine.
Marriages differ, but a sexual relationship is pretty much a given, even when there are disagreements about frequency or the parties' skill level is low. When it is not a given, and if physical ailments are all ruled out, then it's perfectly legitimate to believe that the party is either interested in someone else, utterly uninterested in sex (e. g. they are asexual), or they are gay. This is particularly true early in a relationship (people in their sixties are going to need rest but it doesn't mean they never have sex. But normal, healthy people in their twenties can generally engage in sex at least once every four months).
But no matter what, at the absolute minimum, he should be doing more than coexisting with you in your own home.