My husband is one of two boys. Both our family and his brother's spend a ton of time with my in-laws -- it helps that we live close by, and that my mother-in-law is awesome. He talks to both his parents probably once a week, we vacation together every year, and we get together about once a month if not more. I'm hoping for the same when my three sons grow up!
That said, my husband doesn't have long phone conversations with his mom about his hopes and dreams like a daughter might. - but he's a pretty reserved guy, and doesn't really have those conversations with me either.
My own three brothers were all close to my mom as well. When she died, I think they took it the hardest (especially one of my brothers, who had been her biggest tormentor as a kid). Even now, without my mom around to be the 'glue' that she always was, my brothers remain very close to me and my dad. We speak often, and we see them several times a year despite distance.
If you have a warm, loving relationship with your children, and model a good example of healthy family dynamics (between you and your husband, and you and your extended family) I think it's reasonable to expect a fulfilling adult relationship with your sons. If you're a crazy controlling shrew who shuns your in-laws, and your sons end up being drawn to the same sort of woman, then you might be out of luck
