Ever since my marriage starting falling apart I shared what was going on with my friends. Many were friends for decades but when I shared they shared back. So many women are married but not happily. So, while I am now single, my married friends are glad to do things with me sans husbands. The men don't provide the intimacy of shared feelings like women friends do. By the time my friends are getting older, they are drained emotionally from detached men. 
We support each other and have FUN doing simple things...and talk!Don't give up on married women friends. They may need your friendship too.

Since all the kids are grown and gone, it was especially hard for me to handle living alone - my first time ever in 48 years.  Three years and 2 roommates later, I'm about to go through being in the house alone.  I like to vacation, and especially vacation at the beach.  Although I've got friends who are single, not all of them like the beach like I do.  So hopefully I will make friends here that have the same interest I do.  At the moment, I'm looking for a trip for Memorial Day and that week, and I may have to do that one alone.

I thought similarly to you in regards to having my friends pay for my dinner etc after I was widowed.  But two friends gave me good advice:A female friend said "Don't worry about it, it won't last forever", and a brother-in-law said:  "People want to do things for you, and don't know what, especially men.  Just let them.  It's as much for them as for you".  It is now over three years since I was widowed, and they were both correct.  They don't pity us, they just love us and care.  Occasionally I have slipped up to the waiter, and paid before anyone knew and told my friends that if they kept on paying, I would start to feel that I couldn't instigate the event.

Especially today.  I'm stuck in Houston, and what little family I have left is in Chicago and NW Indiana.  They all go their separate ways, my friends down here are either with the families (husbands, children) or with other married couples.  It really hits me on the weekends, when I want to go out to hear some live music and have a drink, and I know it isn't a safe thing to do by myself.  But when I go with some of my friends who are coupled, I have a miserable time anyway. 

Fifth wheel, third wheel, and the odd wheel too! I've been single all my life (no dates either!!) so I'll take the A+ on this topic.

Almost all of my friends are in commited relationships and/or have kids they don't have a bunch of free time.  I have been to more kiddy movies in 2009 than any single gal without kids should have gone to.  But I still do love them I just wish that some of the nights they set aside to do things with thier boy friends they would remeber their single friend....

I have been separated from my husband for some time now but the divorce isn't final yet. I actively avoid married couples I used to know because seeing them makes me want to run down my soon-to-be-ex husband and I don't want to do that (that would be pointless and no fun for me or for them).