If you are waiting for a man (or woman) to give you a marriage proposal, how long is too long? Sometimes in a relationship you may get so comfortable in the present that you forget to plan for the future. If you never hear your mate talk in the future tense, that's a red flag. Anyone that sees you in the now as well in the future will mention something related to the future that includes you in the equation.
For women that have been steadily dating a man 2+ years and you're giving everything, but receiving no talks of the future together, you may want to take time to read Proverbs 31. It doesn't matter if you are religious or not, read it.
No matter how much you think you love him/her, he/she needs to step up to the plate. If he/ she doesn't, let him/her go.
Often women hear "Why Buy The Cow when you can get the milk for free?" Men think on these terms and some women do too.
How long are you willing to wait? Jot it down to yourself and keep a reminder for yourself when dating. It's better to let go than wait on something that may never happen. If a man or woman is truly ready to commit and truly loves you, that man or woman will plan for the future with you.