A couple of years ago, I was that unfit blob!
Yes, it's hard to fit exercise round DC who are still a bit young to be left. Do you ever get time away from them? Because the best way to start running is C25K, and you need 20-30 mins 3x a week for that. Any chance?
One thing I didn't know when I started running, which I wish I had, is how very friendly runners are, and how much mutual support there is from those at all levels towards each other. Parkrun s a great way to tap in to that? Can you walk or about an hour at a decent pace? Yes? Then you can Parkrun. If you're not sure, then volunteer at Parkrun (take the DC too - they can be extra marshals, and if you all sign up on like you'll have earned your volunteering reward Tshirt in no time) you get to tap in to the community, and cheer on your new boyfriend at the same time. Win/win.
And don't worry what anyone thinks about your appearance when running. Firstly, everyone gets to be sweaty bad-hair person and no-one really notices because it's just so normal it's invisible.
Secondly, these quotations are much used because they are true. Go for it!
"If you run, you are a runner. It doesn't matter how fast or how far. It doesn't matter if today is your first day or if you've been running for twenty years. There is no test to pass, no license to earn, no membership card to get. You just run."
"Running is not, as it so often seems, only about what you did in your last race or about how many miles you ran last week. It is, in a much more important way, about community, about appreciating all the miles run by other runners, too."