There is a give and take. I deal with the same thing, we have 2 kids together (2yo and 4yo). She loves to boat also, having 2 kids not old enough to go right now means I go, but my frequency is once every other month. I make sure that my wife is happy, the house is taken care of, and my relationship with my them all is good. They all know that they come before my float trips, and our lives will evolve as they get older. I am planning on including them with our float trips more and more every year.
You gotta talk to her about it. Your recreation is as serious as a mortgage, but her happiness is of equal importance also. You need to talk to her about this, don't talk to us. If she is not happy with you going, you need to find a solution. Mutual recreation is a key ingredient in a relationship, so maybe some sacrifice needs to be made on her part and yours. If you can do something that makes her happy and feel important and meets her emotional needs, then she will be willing to make a sacrifice to let you enjoy a day on the water.
I don't push my luck right now, but when I leave for a float trip, she is happy to send me off to go rafting for a day or two. I am sure some of her kind words and love are to make me feel better, because I know in her perfect world I would do something with her and the kids every Sunday. But I have days like today, we went to a monster truck show, and all 4 of us had a great time. She went to bed happy, the kids were in heaven, and I have a great time too. Days like today make it much easier for me to have her approve of my next day on the water. Hope this helps...