My ex bf has been more than a father to my 10 year old and so its a bit of a complicated situation, and sometimes I dont know if I am doing the right thing here....do I follow my heart and my happiness with my bf, or do I sacrifice that happiness for my son and my ex? I am sure my bf will love my son very much, he is an amazing guy and I think we deserve the chance to be happy together and I think my son will get to love him too.
You do what is best by
you in this situation. How happy is your son going to be if you are in a relationship you don't really like? Maybe it's fine for now, but five years down the line? Ten? Is it still going to be okay or are you going to always wonder about the "could have beens"?
I was in something of a similar situation when I met the man who is now my husband. I had been dating someone for four years and we were six months away from the Big Wedding Of My Dreams, which my parents had laid out their life savings for. Talk about pressure! I felt very much as you did, that my ex is a GREAT guy (and he is) but that the relationship was lacking a connection, a spark that I felt with my then-friend from the UK. It did come down to making one of the most difficult decisions of my life, but a million miles and one wedding ring later, I know I've made the right choice. Some things you just have to do for you. Yes, it's a risk, and yes, it's a big move. You'll probably even get a lot of BS for it like I did. If you're as lucky in your new man as I was, then it will all be worth it in the end. Not easy by any stretch of the imagination (in my case there was a lot of money on the wedding, my parents hadn't even met the new guy when I called things off, and my fiance-at-the-time was and remains the nicest, sweetest human being alive...he just wasn't for me...there were a lot of bruised feelings. I lost friends, lost the relationship with my ex's family, people took sides even though it was an amicable split...it was a mess) but wholly worth it.
Where do you think education is better? The US or the UK? and do you guys think is easier for a brithish to get used to the States or for an american to the UK? ( I know it probably depends on the person)
I have always wanted to move to the UK, but I will do whatever is best for all of us. How complicated is to get the visa when you have a kid? And do you think it will be better to go to the UK or to stay in the US? sorry...too many questions 
I'm no real judge of this, but I do know that the UK values their teachers more than the US does just from an employment perspective! As I don't have children yet, I can only speak from the hypotheses drawn from conversation with my husband wherein we compared our schooling. We decided that the UK was far better education-wise for our (future) progeny, simply given the BS that goes on in the local (fairly good and reputable) American schools I went to. My husband went to private schools and our kids probably will as well, so I know that makes a difference too.
Neither my hubby nor I have had any particular problems adjusting to the other's country. I lived in the UK with him for two months and then he lived in the states with me for the better part of a year before we decided we wanted to move back here, and both of us seemed to adapt fairly well. I think that's just going to depend on the personalities involved as opposed to how easy a culture is to adapt to.
I prefer it here in the UK, but we did something not everyone could afford to do-both took a chance in the other's country for a while. If you can, I highly recommend doing a "test run" this way, just an extended holiday of sorts (a month or two), to see how you like it. You won't be able to work and there are some aspects of daily life you might miss, but on the whole there's no way to see if you will adapt other than just jumping in.
Good luck! You have some tough decisions in the end there, but I still maintain you need to make them for you. Not your mom, not your son...this is and has to be purely for you.