To validate someones feelings is simply to acknowledge what they are saying or how they are feeling.  Some people suggest repeating their words back to them.  But it is simply, acknowledging that you heard and understood them.  I ask this of my guy all the time.  I can pour out some true feelings and he doesn’t say a word.  Or he will start talking about what is bothering him.  Never validating what I just said to him.  When someone talks they want to be heard.  For example:

Not validating:

Me: I feel like we are growing apart and it seems like you don’t care anymore.

Him: I feel that way too

Me: I try to show you by making dinner last night and suggesting we have a date night and go to a movie

Him: I said I would go

Validating:

Me: I feel like we are growing apart and it seems like you don’t care anymore.

Him: you really feel like we are growing apart? I don’t mean us to.  I really do care about you and I don’t want us to grow apart (obviously if he didn’t feel that way he would respond differently but the point is that I would know he knows exactly what I said)

Me: I try to show you by making dinner last night and suggesting we have a date night and go to a movie

Him:  Yes dinner was good and really nice of you.  I am sorry I didn’t take it serious to go to the movie, lets try again and go tonight.

I hope this was helpful : )