I (f19) and my boyfriend (m20) have been dating for not that long, maybe about 3ish months and he is my first everything so I don’t have much experience with anything. In the beginning when we would have sex it would be somewhat often and we built up to, most in one go, three rounds and he came every time. Recently, we get into the mood and I usually suck him off and he comes fairly quick and he expresses how he’s extra sensitive and doesn’t know why. Then we try going into sex and typically during the second round we keep it going but he gets soft and doesn’t come. At that point we don’t keep going but I tell him that it’s okay for us to stop. I make sure to reassure him that it’s totally fine and not to stress about it because I can tell in his face that he’s frustrated that it gets soft. I’m worried a little on my part because I wonder if it’s me. Like if it’s just my body that isn’t satisfying him enough and due to that he gets soft. But I also notice that he gets exhausted and worked up a little and that may be the case too. Maybe he’s just wearing himself out and so he can’t focus much on the act of it. I’m not entirely sure but he seems to be getting frustrated and really bothered about himself and his capabilities but I don’t see it as him doing something wrong I feel it’s more me. But idk honestly I need help.