He's only 7 weeks old, so it doesn't surprise me one bit that he has trouble sleeping unless he's in your bed or in your arms. As he gets a little older, that will get better naturally. One thing that I did in the mean time was lie down on my bed with my son and nurse him to sleep. Once he was asleep, I would slowly and carefully roll away (or just nap myself :-).
As they got older, they would nap for longer stretches, but it wasn't until they were around a year old that either of them napped for more than 2 hours.
We coslepts with both boys until they were 17 months old, with no issues transitioning them. I'm sure there are some parents who struggle with this transition, but I have seen just as many posts of parents struggling to get their babies to sleep in their own bed at night. I skipped that struggle altogether by having them with me in my bed.
Don't let co-sleeping stop you from being intimate. First, keep in mind that the bedroom is not the only place you can do this. Also, once your son is asleep, you can move him somewhere else for just a little bit. Stack some blankets on the floor (just soft enough, but not too soft), or put him in his car seat or bouncy seat (which are also good places for him to nap or sleep). Just be a little creative. You'll find ways!
If you don't want to cosleep, that's one thing. But if you are only thinking of changing that because it's what you are "supposed" to do, don't. Do what works for you and for baby. This is my rule for that first year: The best place for baby to sleep is wherever baby will sleep. Because when baby sleeps, you get to sleep.