is it a deal breaker??

so i am dating a divorced man that has 2 older kids and a 7 year old child. i adore them and i admire him for being the man he is. He's had full custody of his older kids since they were babies and He has joint custody of his youngest. One of the oldest kids lives at home and the other has moved out. The youngest will come over 3-4 times a week...Hes living in a 2 bedroom apartment and he shares his room with his youngest. I stay over often and we've tlked about moving in. today, i mentioned to him that we need to get a twin bed for his kid to stay in his brothers room. he legitimately sounded as if i told him to never talk to his child again. He had his feelings hurt and said he misses him and that he wants to spend all the time he can with him. I can understand that, however he can't expect for us 3 to share a bedroom. i just dont know how to go about this, without sounding rude or inconsiderate of his feelings. What should I do? He's a great guy but the bedroom is suppose to be a place of intimacy and its only intimate on days his child isn't there....when I'm done washing all the bedding since he leaves drool marks everywhere. :(