That's a tough situation. I know of so many boats that have gone into disrepair because their owners can't spend sufficient time using and maintaining them. A moored boat is a little harder to get to than one sitting at the dock. Many people with a boat in a slip manage to "use" the boat just by stopping by and using it right there at the dock as a little "condo" away from home. Without going out sailing at all, they're happy to do something with their boat.
Only an opinion, but if I couldn't find a way to use my boat with more frequency than once a month I'd likely get rid of it and wait for a better time in my life to own a boat and use it. For more than 20 years my husband and I didn't own a boat but instead rented/chartered because we could only get away to sail infrequently. We did own a small sailing canoe! for little weekend adventures though
When we were rebuilding our cruising boat, we owned a 30' sailboat to keep us "sane" and focused during the big boat rebuild and we would often just go to that smaller boat (on a mooring) and sit, have a beer, relaxing on a weekday night.
Keeping your boat--there is no "addition" to family from infant to geriatric which cannot be enjoyably accommodated on a boat. If you have small children, there are special safety considerations but there are many people who successfully bring children up living on small boats and big boats alike. If your spouse has worries, buy him/her the PBS documentary video IceBlink
or have the spouse read Into the Light
by Dave and Jaja Martin.
Sometimes, just making the commitment to do something "different" can really help. If you can't make a family day of it, perhaps you can have a Friday night sail (or motor if no wind) with your spouse each week. Perhaps just a weekday evening sitting on the mooring, reading a book or cooking up a little meal? Your moored boat can be a great place to retreat from the world. I know a couple who live in New Jersey and primarily sail their small boat in the Fall, Winter, and Spring seasons--because they like the quiet of their sailing grounds during the "off seasons." The fellows favorite thing is to take a good book, a bit of wood for the little stove aboard, and go drop the hook in a quiet cove...sit and read and relax.
If boating is important to you, make it important to your children as well. I know a fellow who races his little Catalina 27 every Wednesday night in the summers with his buddies--he also has a two year old boy. His wife doesn't sail and chooses to stay at home and do other things. In addition to racing, once or twice a month he brings his boat in off the mooring for a weekend and takes a slip at the marina--he brings his son to the boat and they "play boat" for the weekend. He does maintenance (which he could do in 1/4th the time without the boy there!) and his son "helps." He's been doing this since the boy was 14 months old, btw. At the end of the day Saturday it's a trip up to the marina showers to clean up all the evidence of their play and usually on Sunday mornings there's a father-son feast being cooked on the little taftrail grill. They set the boat back on the mooring Sunday afternoon and go home after their weekend of "playing boat." I love seeing them together--and the father hopes that his son will grow up loving sailing as much as he does. This upcoming summer, when the boy is three, the father plans on taking him sailing during the Wednesday night races and also sailing/anchoring on the Catalina 27 for their weekends "playing boat." Since he's solo on the weekends, he doesn't want to sail with the boy until the boy understands more about what is going on.
If you don't enjoy using your boat--perhaps selling it is a good option. If you love your boat and enjoy using it, don't let others define what is "usage" but rather figure out what you would enjoy and do it. If you'd rather sit on the boat and read by candlelight (ah, so romantic!) ...or just have a glass of wine and reflect on the weeks activities...while you do some bit of maintenance sitting on the moored boat on a Tuesday night--well, I think that's a wonderful usage between sailing trips. Life goes by at such a fast pace, finding ways to stop for a moment can be really a good thing. We don't know your life nor the maintenance requirements of your boat, but I hope you can find a way to make it all work out.
Cruising is a choice we make--part of the cruising life for many people is learning how to "turn off" the "extra" stuff ...deciding what is real/needed and what is extra/constraining and keeping us from doing what we want to do. Then...we focus on just what needs to be done so that we can take the time to enjoy our lives while cruising-or doing whatever else is right for us. Each of us decides at some point how much money is "enough", how much work is enough, how much "stuff" is enough. Our lives are all full--but full of different things and different activities. We make those choices.
Good luck to you in solving your boat time issue.