Firstly, you express yourself so well here, and your description of your feelings makes them sound really powerful, which of course renders them all-consuming and hard to break down at times.
You sound empathetic based on your desire to wait for him, and with the volume of emotion you have for him, it's common to experience that numbness you talk about. I would take that numbness to be a subconscious protective mechanism shielding the particularly tough feelings from you.
Are you still communicating with him? It might be easier to handle the thought of your relationship if you minimise the number of reminders you receive about it. For instance, if you often look at his social media profiles or your past conversations with him, I would suggest you slowly cut back from that.
When we build relationships with people, we generally not only feel obligations to them, but also expect things from them in return, which they may not be capable or willing to give. Reducing the amount of contact you have with him could make your relationship feel less obligation-based, which would make it less heavy-feeling to think about.
In regards to your feelings of guilt and selfishness, it's not at all a bad thing to want love and affection. Almost every person is a little selfish in that sense; it's typical to want human connection and happy things for yourself. Do you feel undeserving of love/of him? I think that it would help to cultivate your love in things that aren't human, if that makes sense. For example, I have cacti that I care for (not that they need much care) and I can pretend that they love me even though they have no consciousness, while they invigorate my own love for nature. This can also apply to pets if you have any. Creating a space for something personal to you could ease the dependence on lingering thoughts of other people.
Remember to physically nourish yourself if you feel able to, and try to sleep if you can too, preferably away from distractors like phones.
I have hope that you'll get through this!