Life after the breakup

It’s been 5 months since the breakup and I had a reset since she reached out to me before thanksgiving, thinking we were gonna get back together. I just think it’s crazy how before the breakup I was just eating fast food, snacks, drinking beer, not working out and sleeping late and now after the breakup I started to workout more, I went from 200 lbs to 188 lbs, I don’t like fast food anymore, I don’t eat sugar. I try to eat healthy most of the time now. Do we just get comfortable in the relationship? Does the relationship take a toll? Or maybe just both.