Hi all - I am new here, and I'm hoping to get some advice on an issue that has come up related to sleeping arrangements. I have been dating my BF for almost 2 years, and we have been discussing getting engaged. BF has 50% custody of his son, who is 6.

So I'm at my BF's house, and it was the first time I was there and planning to spend the night while his son was also there. My BF's room is on the first floor of the house, and his son's room is on the second floor. At this point in the evening, my BF had tucked his son in, and we were in my BF's room getting ready for bed. Then, my BF says, "When my son is here, I actually sleep upstairs in the guest bedroom so that I can be closer to him, in case he wakes up in the middle of the night and needs something." I was a bit taken aback because there had been NO mention of this beforehand, but I decide to go along with it. Well, that lasted for 3 days, and then I decided to pull the plug. I am no longer spending the night while his son is there. This is my thought process:

• BF won't give me any time frame for when this is going to stop. If we get married, sorry, but I'm not going change where I sleep and go to a guest room 3-4 days a week because his son is there. However, I would certainly consider doing it for a short-term period of time, with the intention of it eventually stopping.
• BF has no explanation as to why he is doing this and refuses to give me one. However, he DID say his son is still co-sleeping with BM every night - and apparently his son wants to sleep with him, too. Maybe he sees this as an acceptable alternative to that? He wouldn't admit that's how he felt though, when I asked. He fully recognizes that BM is doing a disservice to their son by continuing to co-sleep, but he won't say anything to her about it.
• Similar to other stories on this site, my BF's son rules the roost in the house. He has to be told at least once a day by my BF that he isn't the one in charge. I can't imagine talking to my parents the way he talks to his dad...I would have been grounded for life. There is constant backtalk along with demanding, rude behavior. BF is definitely a guilty dad, but he is working on stepping up with discipline (after I gently told him that his son was going to be in for a rude awakening once he got into the real world - this conversation happened after his son told his daycare provider that he didn't need to listen to them, so I spoke up about the concerns I had at that time). With that said, his son is usually very sweet towards me. I'd consider us to have a good relationship. 
• The distance between son's room and BF's room is literally the length of the stairs. It's not like it's a considerable distance. Couldn't he just call out to his dad? Or...walk down the stairs to my BF's room?! BF always leaves the hallway light on too while son is sleeping, so it's not like he couldn't see or something while going down the stairs.
• I told my BF that by sleeping in the guest bedroom, he is sending his son the message that he has control over where I and my BF sleep. He is also sending the wrong message about adult relationships - if we get married, this models to his son that it's okay to put your spouse on the backburner. I will not sleep in a separate room from my husband 3-4 days a week, especially when there is NO end in sight to this happening. 

If there weren't other power struggles in the house, this probably woudn't bother me so much, but this is just one more thing to add to the list. It's gotten to the point where during an argument I told BF that it seemed like he already had a spouse - his son (and this argument wasn't just about the sleeping arrangement, but other things as well). I'm also very frustrated that this was NEVER brought up or mentioned to me until literally the night of me staying over the first time. 

Am I being unreasonable? Thanks for your honest feedback. I'd welcome any thoughts/suggestions.