ITAP for when you're surrounded by something desirable or valuable, but you are incapable of obtaining it?

The best I could think of is "dehydrating in an oasis" but there is no way this is an established idiom.

I think I would like to see multiple solutions for this problem, but let me know if this subreddit doesn't work this way. The reason is because my question could be interpreted a few ways -

One example could be the following situation: A young man and young woman who are friends both walk into a cheese shop. however, the young man is lactose intolerant, and the young woman believes her friend is missing out on all the great cheese he is missing out. She jokes to him that he is surrounded by something **she** sees as very desirable (ie. the good cheese) but that he is unable to get due to food intolerance.

a second situation could be something like this: It's the same two people from the previous example. The young woman and the young man are both in a speed dating event. The young man is heterosexual, but he is incredibly nervous to talk to the other women. So his friend jokes to him that he is surrounded by something **he** sees as very desirable (ie. dating opportunities), but that he is unable get because of nervousness.

These two situations are different. The first one is something she sees as valuable that he is missing out on, and the other is something he himself sees as valuable that he is missing out on. The specific examples I'm using isn't as relevant as the underlying pattern of not being able to obtain something desirable despite being surrounded by it.

I'm pretty sure there are two different idioms for each situation, but could somebody help me out?