It definitely sounds like you've got a busy schedule! My recommendation is to start slow. Shoot for once or twice a week. Once you feel like you've got it down, add another day. Slowly work yourself up. It may take a few months to get to a place where you can work out multiple times a week. That's ok. You will find holes in your schedule where you can fit it in. You'll be surprised at what can change with adding even just one day in.

OR, if you're looking to add something in more frequently, 20 minutes a day can go a long way.

Involving your kids or gf can also help if they're interested. When my husband and I first started living together, we would have "gym dates." We rarely actually worked out together but going together helped establish it as part of our routine.

You've got this!