Let's say you are receiving SS benefits then you got married, and then he passed away if God willing. Now after his passing away can you choose to get his SS Benefits specially your SS Benefit is lot smaller? Do you have to be married for 10 years to get entitled for it if it allows you for it? Or it doesn't matter so long that you were married?
You normally must be married for at least 9 months to qualify for widow's benefits, in addition to meeting other requirements (https://www.ssa.gov/OP_Home/handbook/handbook.04/handbook-0401.html).
If you are already receiving your own retirement benefits when you become entitled to higher widow's benefits and you are at least full retirement age, you would continue to receive your own benefit rate plus the difference between your benefit rate and your deceased spouse's benefit rate. In other words, your total benefit rate would then be equal to your deceased spouse's higher rate.