Don't stop at one. Get a couple different sizes. You might find you like the bigger one when you're really into it. It's not always about insertion, sometimes just a good rub works. Now that you're single figure out what really works for you. This will help you out with the next relationship. The more in touch you are with what makes you feel good the better you can help him please you.
I personally would advise against the fwb because if you're anything like me sex is connected to emotions and you can get heartbroken even on accident. Not to mention possible pregnancy and you have to trust the person your with. I don't think I could have sex just to have sex. But orgasms can be therapeutic so a favorite dildo is a must. lol
I had a dildo but it was either too big or I was too nervous to put it in ? I'm hoping to order one soon.
Dildos are your best friend. :-) I don't advice vibrators though because you don't want to desensitize yourself for the next man in your life.