I'm 27. Have 2 kids of my own. Been with fiance for 6 years. Got engaged a year ago. I can already tell his kids will be the reason we end things. 

My kids are 7 year girl and 8 year boy . His kids are 8 year boy and 9 year girl. Yes 7,8,8,9. They bump heads alot which is given being close in age. But I tell you what...his kids are devilish. Spoiled, rude, whiney amd ungodly annoying. I cringe when it's their time here. They do every other week but are here 2 days of her week. So here most of the time.