Guy?! You think "Sam" is a guy? Okay, I won't excuse your invasion of his privacy, because it is always wrong to go through your SO's phone, but I will say that you're sending mixed signals with this Sam character. Why would it be a problem if he didn't tell this "guy" that he was in a relationship? He found "him" attractive, but didn't want to have sex with "him"? You two have been in a relationship for a long time (5 years)... I think it's about time you had the "where is this going" talk. It sounds like you're a little insecure in the relationship, and perhaps for good reason. Maybe this thing has run its course? Are you looking for a long-term commitment that he's just not ready for? Whatever the case, don't get it in your head that you're going to tell him how he can atone for "what he did". You don't need to tell him how he can change... you will NEVER, EVER change another person with any measure of success. The only thing you can change is you, and I think you owe it to yourself to do the "relationship check" to make sure this is what you want. Not "if he changes this our relationship will be perfect", but "can I love and trust this guy, even though he didn't tell me about this person he met and talked to?" After you address that, you need to address the invasion of privacy on your part... how can you question HIS trustworthiness when YOU appear equally as untrustworthy?

I was kind of confused by the use of pronouns as well, but I'm assuming that the OP is a man, and this is a gay relationship.

I'm not going to get into whether or not you should have invaded your bf's privacy. It is clear, though, that your intuition prompted you to "snoop" - and what you found confirmed your suspicions that something in your relationship isn't right.

Kiddo, people don't collect phone numbers (and then USE them) if they're content in their current relationship. My advice is to get past the details of this one act, and to deal with what's wrong in your relationship. You both will either commit to staying together and fixing what's wrong, or end it as cleanly as possible. (And Notinthemood is EXACTLY right - you're not going to make him change.)

you already know why people exchange numbers...it's so they can talk to someone again, and more. I would have bought for a second oh I got his number because he wants to buy this drum set I'm selling/my friend is selling, or whatever-but to just say "I didn't think I had to tell you everything I do?" Hmmm.....

I'd just be aware that he may want to date other people in addition to you. If that's not cool with you, make sure he knows that (I'm pretty sure you already have,) and if he cheats, he cheats. But get your heart ready in the meantime because it sounds like he wants to date other people.

I think that when someone gets defensive when asked a simple question like 'who is he?' to the point he has to say 'I don't have to tell you everything I did,' something is fishy.

There are so many possibilities that might have happened, they might just flirted and exchanged numbers and your bf might have thought that it was a nice ego boost for someone like Sam to be flirting with him or etc. Your bf might be tempted to cheat but didn't go through with it, etc etc.

But it does seem that something isn't quite 'right' with the relationship. Maybe it's hit a crossroad where you have to decide to break up or stay together or etc. Only you and your bf know what's really going on on a day-to-day basis. Take a good look at it and good luck to you.

I dunno. It could entirely be innocent. I know my boyfriend got annoyed with me asking who people he says hi to are... but I was kinda turning it into a game of "co-worker or resident?!" Mostly because I was curious who his coworkers are after his entertaining stories about them (he's an RA, and RA's are crazy).

I mean, I'm sure that everyone who knows him or me knows that we're together, but at least for me, it's not the first thing I say to someone if I'm just trying to be friends, but I make sure to mention it if they are getting to flirty, but friends find out soon enough anyways.

And looking through someone's phone would likely get the person on the defense really fast. I know I would get a little defensive if I knew my boyfriend went through my phone and was all "WHO IS THIS PERSON!?" when he came upon someone I was trying to befriend.

Maybe try to examine why you are insecure in your relationship?

There is not a whole lot more I can add as the above comments are spot on.

I would heed their advice OP.

Good luck!

Hmmm so after looking at your profile I see that you are a straight female. So judging by the fact that your bf considers a man attractive and you are concerned about it, I would have to assume that your bf is bisexual or gay? Otherwise why would you even care if he talked to another dude? I feel like you left out some important details in your post. If you have suspicions that your bf is sexually interested with or involved with other men, please, please make sure that you always use condoms when you are with him and get regularly tested for STI's. Other than that, I think that there is an obvious lack of trust in your relationship. You looked through his phone because you felt suspicious. Why do you not trust him? Has he given you reason to be suspicious? If you suspect him of cheating and do not trust him, then the relationship probably will not last. Frankly you sound really paranoid to me and unless you have a strong feeling that he is cheating, I don't understand why you would feel the need to go through his phone. Basically, I do not think that he has to change, I think that you do. If you cannot trust him then the relationship has probably run its course because trust is an essential part of a healthy relationship. Good luck.