OK, there are kids involved, correct? So going on the statistics (and my own personal experience) being how women do a substantially greater share of work around the house which includes inventorying, planning, shopping, and then the actual work at the house, it may be beneficial to you to make sure that you are doing your share, at a minimum, in HER eyes. With kids, she's (again I'm assuming) doing the majority of the work so you going off boating may just seem like her getting left with the kids yet again. Have you sat down with her and discussed the distribution of labor and responsibilities? Do you make sure to take some time to take the kids so she can go run off with girlfriends or just get errands done without also being a "mom"? How about planning (yes, planning is a lot of work) babysitters so you two can go do fun stuff that does not include managing the kids? Now I am not accusing you of anything, just talking about a lot of issues that friends with kids have that may be useful to think about. Doing your share of "guys" chores may not be enough. Do you clean the toilet AND the wall next to it? If she feels like she's getting left behind to yet again babysit (although a mom would never say that, it can feel like it) I wouldn't be surprised at all at her reaction.
Lot of good advice from others also, so I'll just stick to this aspect of this.
I am a river, babe - I've got plenty of time, I don't know where I'm going, I'm just following the lines..... - "We are water" by Shaye