If you want to add some space in your rows/columns, can give this a try.

separated.dart

import 'package:flutter/widgets.dart';

class SeparatedRow extends StatelessWidget {
  const SeparatedRow({
    @required this.separator,
    @required this.children,
    this.mainAxisAlignment = MainAxisAlignment.start,
    this.mainAxisSize = MainAxisSize.max,
    this.crossAxisAlignment = CrossAxisAlignment.center,
  })  : assert(separator != null),
        assert(children != null);

  final List<Widget> children;
  final Widget separator;

  final MainAxisAlignment mainAxisAlignment;
  final MainAxisSize mainAxisSize;
  final CrossAxisAlignment crossAxisAlignment;

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: mainAxisAlignment,
      mainAxisSize: mainAxisSize,
      crossAxisAlignment: crossAxisAlignment,
      children: [..._intersperse(children, separator)],
    );
  }
}

class SeparatedColumn extends StatelessWidget {
  const SeparatedColumn({
    @required this.separator,
    @required this.children,
    this.mainAxisAlignment = MainAxisAlignment.start,
    this.mainAxisSize = MainAxisSize.max,
    this.crossAxisAlignment = CrossAxisAlignment.center,
  })  : assert(separator != null),
        assert(children != null);

  final List<Widget> children;
  final Widget separator;

  final MainAxisAlignment mainAxisAlignment;
  final MainAxisSize mainAxisSize;
  final CrossAxisAlignment crossAxisAlignment;

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: mainAxisAlignment,
      mainAxisSize: mainAxisSize,
      crossAxisAlignment: crossAxisAlignment,
      children: [..._intersperse(children, separator)],
    );
  }
}

Iterable<T> _intersperse<T>(Iterable<T> elements, T value) {
  return elements.expand((el) sync* {
    yield value;
    yield el;
  }).skip(1);
}