Hi T. -
I know you'll get lots of great advice about how to teach him to sleep independently, so I thought I'd offer some random other thoughts......
Just fyi, my son always had to have his feet on my bare stomach or his hands near the skin on my chest. He had only very mild sensory problems, so I think it was more just his personality. It's very common from what I understand. He's 10 now, and still loves to cuddle. imho, I don't think your son wanting to have his feet on you is "strange".
Your son's behavior of sleeping with you has been created over 3 years of time, so I wouldn't expect to change it over night. Would be nice if it worked that way, wouldn't it?!
I know it's said that "consistency is key", and I believe it. But I also know what it's like to be a stressed out, exhausted single mom who has great intentions, but can't always follow through. Don't beat up on yourself just because you give in once in awhile - we're all human. Just refine your goals (getting him to sleep by himself, getting him on a schedule), and begin again with renewed gusto.
Can you try to offer him simple, concrete choices? For examp: Do you want to listen to this cd or that one while you get ready for bed? This book or that one? These pj's or those? The idea being to offer him some sense of control over his life. He can't control whether or not his dad comes to see him, but he can control some things. For the big things (When and where he goes to bed, etc) he still needs to rely on the adults in his life, even if he insists he's in charge. (Amazing how strong-willed our little ones can be, isn't it?)
I didn't quite understand your thoughts about stuffed animals, and don't mean to contradict them. Personally, I think they're a good idea and would be less apt to create loss of independence than co-sleeping might. If you're worried, you might look at (if you haven't already) normal developmental milestones info such as: http://www.cyh.com/HealthTopics/HealthTopicDetails.aspx?p...
I think it's a great idea to get him used to going to bed by himself before you start dating.....any new adult in his life may feel threatening to his 3 yr old self and make it more difficult to encourage independence.
One other thought - does he have regular periods of one-on-one time with you during other times of the day? If going to bed is his only "sure" alone time with you, it might make it that much harder for him to give it up.
Best of luck to you.