I'm a father of 2. My experience is this. I saw my kids every weekend and holidays as much as I could. But from the moment the relationship breaks up the relationship with your kids is changed forever. That close bond is severed and the gap will forever widen.
When they are very young and too small to understand things are not so bad. They are excited to see you and it's great spending time with them but here's the thing .. for me it got steadily worse as the kids grew older. I was always just the weekend parent and that close bond with my kids slowly faded. They just get used to you not being there.
So I met another woman, and she tried to isolate me further from my kids. Wanted to start her own family. Had to make a difficult choice between her or my kids. Chose to leave her. But in the end it didn't make any difference. My ex remarried and refocused my kids attention to the new step father. My kids grew ever more distant.
When my daughter turned 18 she and my CS payments ended she didn't want anything more to do with me. Even changed her last name to her step father's. My son I see occasionally but it's me who has to keep the contact going.
But I did find the strength to carry on.. I keep busy business and hobbies, eat healthy, exercise body and mind. and focus on myself. Have a couple good mates. Yes it's tough.