I’m 21 and he is turning 21 soon.
You should know that giving into these unchaste behaviors will only increase the pressure on you to give in to sex.
Also you sleeping in the same bed is making this worse for him. When he has urges and temptations you are right there right next to him in bed, (the place most associated with marital relations), this will make it difficult for him to turn away from these temptations. If he was by himself he could more easily turn his thoughts to something else.
Also I hope you are not living together. (This is a bad idea for many reasons, but again make it somewhat illogical for him, that you would not be having sex, even though otherwise living like a married couple).
You have only been dating your boyfriend for 5 months and you are only 21, yet you seem desperate to hold on to him. If he can’t go some time without sex and because of that leaves you or cheats on you, then he is not marriage material and be happy you did not end up in a marriage where you are constantly worrying if you husband is going to cheat on you or leave you. (Marriage is not about unlimited sex, there are many periods of abstinence even in marriage, which is all the harder because it is your spouse not just a boyfriend).
I won’t say he doesn’t love you or respect you because he is pressuring you. He is young and experiencing great temptations, and seems to genuinely be trying respect the boundaries you have established (no touching in bed, though I wonder how you notice he is having erections in bed if you are not touching?). Though if he does cheat on you or leave you for no sex, then I would question both of those assertions.
I am sorry that your relationship has advanced this far so early, as it is hard to turn back the clock and stop doing things you have already started. You and he need to take a step back, you need to get to know each other on a non physical level. 5 months is not (usually) enough time to get to know someone on such a level, especially if you have been substituting physical closeness for intellectual, emotional, and spiritual closeness.
As the old saying goes, “why buy the cow if you can get the milk for free?” This is especially true if you are already so mistrustful of him to think he will cheat or leave if you don’t give him the “milk.”