A question which alot of people I know ask me, how can I tell if my partner is cheating? well there's a few ways to tell.
1. they start acting funny around you (act guilty)
2. they buy you lots of things.
3. become more effectionate or the opposit
4. breaking dates with you.
5. stuttering when they talk
6. lying often.
why do people cheat? and i'm saying people because not only do males cheat but females to also. well i'm not expert as to why, but I do know from personal experiance.
1. tired of the person/relationship
2.no longer have a "spark"
3.want to try something new
4.need to find a way out
5. in an abusive relationship and need comfert from someone else and one thing leads to another.
6.flat out don't care who you hurt and you cheat just because.
7.want to feel loved and think the more the better.
and so on and so forth. well I hope this answered some of your questions, let me know if you have more, i'll be glad to help.