previous affairs before marriage?

I don't know what I can really suggest, but I can definitely tell you one thing.

you should neither commit or not commit, what will a guy do in future. all you should do is, get the guy and girl talk as much as they want to, help them to have more time to make decisions. Their life, they should decide.

One night stands isn't a yardstick to measure anyone, absolutely so when he/she is a bachelor. that said, personally, I find the concept of one night stand a bit unflattering.

previous affairs before marriage?