L.,
What is "me" time??? Just kidding. When my children were younger, there was no such thing. Once in a blue moon I might get to go to the store by myself. But, I did not do stuff just for me. I spent those early years devoting myself to my kids and my husband. Looking back, I think that I could have been a much better mom and wife if I had made a point of taking a time out for myself at least once a week.
I worked when we had our first two children (full-time). I even went back to work when our third was born. However, I quickly learned that I could not handle working full-time, getting three children ready each morning by myself, getting myself ready each morning for work, getting the kids to daycare by myself, picking the kids up from daycare by myself, packing everything each child needed for each day, breastfeeding the baby, getting up at all hours for the baby and the 1 1/2 year old, and all the other stuff that went along with everyday life at that point. My husband didn't travel at that point, but worked long hours that began very early. So, after 6 weeks of working with the 3 kids, I cut back to part-time. I didn't become a complete SAHM until we moved 400 miles from "home."
Please know that I only share all that to share how lucky I believe you are by being able to stay home at this point.
Now, back to "me" time...I honestly think that you should work some "me" time into your schedule each week. Does your gym offer childcare? If you enjoy the gym and it offers the childcare, get on a solid schedule and go work out. You are also giving your children some much needed time away from you to learn valuable skills (social skills and self-confidence for example). Find time maybe after you put the kids to bed, or get your husband to watch the kids for an hour, maybe once a week and take a bubble bath and enjoy a good book while relaxing there. The amount of time you take isn't really the point, IMO. Just making it a point to take a break, take a deep breath, relax, and regroup are very important to maintaining sanity as well as maintaining patience and strong relationships with both your husband and your children.
I would also encourage you though to have 2 "other" dates each month. I personally love to have a girlfriend date to go shopping, to a movie, get our nails done, or whatever you enjoy doing with some of your girlfriends. I think it helps you to remember that you aren't just a wife and a mother. Then I would also recommend hiring a sitter, begging family if need be, to have a date with your husband. It doesn't even have to cost money. But also make "hubby & me" time.
Good luck in your quest to find "me" time!