I think if he really wanted to talk to you, he would have.
I’m sorry if that is very direct, but that just seems obvious to me.
You don’t say how long you’ve been in the relationship. If it’s very early, and you’ve not established exclusivity, it’s probably not such a big deal that he hasn’t called or sent you a text. That would be within reason for a new or relatively new or non-committed relationship.
If you’ve been together for several months and you usually talk or text each day, and particularly if you’ve established a committed status, I think it’s odd that he has no interest in contacting you. Sure, he’s on vacation with his family and is busy with his brother’s wedding festivities, but if he has made no effort to contact you, what does his behavior say? It may have nothing to do with cheating. It just sounds like disregard.
I don’t buy the whole “cost” thing. He’s in Mexico, not Mars, probably at a resort that has wifi, and one quick call in a ten day period certainly would not break the bank.
My husband’s home office is on the opposite side of the country from where we live. He travels very frequently and often internationally for his business and has since we’ve been married. We deal with most every different time zone in the world and still find a way to call and text each other, even if it’s sometimes him calling me to say goodnight while he’s just starting his day.
I don’t know whether you’re clingy or high maintenance or whatever. What does seem clear is that he is not motivated, for whatever reason, to be in contact with you while on vacation.
Maybe instead of focusing on him cheating, ask yourself if this is really the kind of relationship you want to be in. You ask if this is “something that should be addressed,” but the person you need to address this with is YOU. Before you even think of discussing this with him, ask yourself, seriously, is this the kind of treatment you want from your partner.