How to not feel inadequate

[MyMushroomsInATimeSlip]

I'm meeting university friends plus DC next week. They're all lovely but I always come away feeling like I'm failing at life. They are all happily married (yes, actually!), successful in their careers, lovely children, exciting hobbies and plans, 4 bed houses. I on the other hand am a single parent to a slightly unhappy and very shy child, my house is falling apart and I managed the bare minimum as I can't cope with stress.
When I'm with friends in a similar situation I feel strong, empowered and like I've achieved something by surviving and parenting single-handedly. How can I stop feeling totally shit after seeing other friends?

Well, if they are actual friends as opposed to 'people you know slightly' then you'll know it isn't a competition.
You'll know that achievement, nor happiness is measured on the size of your house or the level of shyness of your child.

I have friends who are married, friends who are divorced, friends who never married. None of this changes my opinion of them nor my feelings towards them.
I also have friends who own houses in much 'nicer' read expensive areas than mine, and friends that live in much rougher areas than I do. I have friends who don't own houses. I suspect I have friends who owe a lot on their mortgage and friends who have paid it off. I have friends who have much more space in their home than I have and friends with much smaller places. Once again, it makes no difference whatsoever to how much I like them or how I feel towards them or how I feel about our friendship.

I could go on, but I expect you get the gist.

No one knows what goes on behind closed doors.

I have previously been with someone who was incredibly cruel but go the outside world we were the perfect couple with the perfect life.

I like my friends - they're all lovely. It's more how I feel about myself .

@Galassia I totally agree however I know their DHs well and they're all lovely too!