Is it sin?

Ok I'll try to make this short and to the point so when I was in 8th grade I met this girl at school and I really liked her and I became good friends with her family and not make a long story short I decided not to ask her out. Shes now married and has two kids and We kinda lost touch but I recently got back in touch with her and I relized that I still have feelings for her. Which I feel guilty for.
So my question is it a sin that I like a married woman?

Interesting question! Off the top of my head, I'd say it's not wrong to have an "attraction" to a married woman. Married women do not become unattractive simply because they are married. There are certainly married women that, because of their personal qualities or physical traits, I still find attractive either physically or personally. (Though a wise husband will not give commentary to his wife whenever one of these qualities occurs to him.)

What will be harmful is if we allow ourselves (married or not) to dwell on desires, be they sexual or romantic, for another man's wife. Jesus seems to give our thought lives similar weight to our actions(Matt. 5:21-22 and 28), and God's design for marriage is that one man be with one woman. (1. Cor. 7:2)

From these two facts, it seems reasonable to me that romantic or sexual thoughts for a married woman are outside of God's design, since romantic and sexual actions are designed to be between one man and one woman, for life.

And although I can't pull up scriptural support for this, I'd also say that fixating on feelings for someone that is not an option for us will in the worst case lead to adultery and in the best case still leave us with perpetually unfulfilled desires and make us less capable and less open in loving a current or potential future spouse.

Anyone else have thoughts on this one? Great question!

That is a good question.

Is the desire and attraction to another person in itself sin? No, of course not. God created each of us to appreciate the beauty with which He created other people.

But I agree with Paeter, and I think his biblical references are spot on. Allowing ourselves to dwell on and keep the feelings current and active in our minds and hearts is where we start to cross intop the realm of sin. It's natural to look at and be attracted to someone else who is married. But we must not allow ourselves to think "I want to be with her/him." If it's a former friend/flame, allow yourself to remember those feelings that were once there, but you must also recognize that those feelings were then, not now. God allowed two people to come together for a time, but that time is over, and He has something else planned for those two.

Each person we encounter and have feelings for helps shape us for the ultimate end reward that God has planned for us. I admit that I see pictures from old flames and love interests, and I have flashes of what it would have been like had things developed between me and them. But then I remember that God has blessed me with a wonderful fiance (wedding is in April), and I know that this really is God's blessing in my life. And those thoughts for my old flames last only a micro-second, because they are overwhelmed by my live for my fiance.

Hope that helps, and doesn't sound too rambling.