A.J.
I don't think you should have a third child. My sister and I are only three years apart and we are very close. My mom and dad had my brother when we were 5 & 8 and growing up we were never close to him. I think the age difference played a major part in that. Also since we were both girls and pretty close in age, we just bonded so well. I can remember how annoyed we were by the time he was a toddler. I would just keep my focus on the boys and staying involved with them. As for the love, you will always have enough love to go around never worry about that.
~ I hope I was helpful.