I’m going against the grain. My eldest has a different father to my younger two. The teen years were very, very hard, DS1 and DH fought almost constantly it felt like. Every meal time some months. It caused friction between myself and DH, the other two children didn’t like it either, not such a huge age gap between all 3. Now DS1 was a difficult teen, he is AUDHD and can be hard work, he also never ever backed down even when he was wrong, he wasn’t always wrong. But he often was rude, difficult, overstepping.
I didn’t think DH and I would make it, I was very, very protective of DS1 and frustrated that it seemed the other two were never pulled up by DH. I cannot tell you how many times we discussed it. round and round in circles we went.
DS1 is now 18, he has a fantastic relationship with DH. Really good. If I had split from DH it would have been so disruptive for all 3 children especially my eldest. And frankly I would have been miserable as well.
I honestly think that sometimes - particularly with male teens they butt heads with a male adult for the very sake of it. And men just don’t back down or pacify in the same way women can/do and probably teen boys don’t cause the grief to their mothers they do to males. It wasn’t always my teens fault though, DH overreacted as well.
I would say look at your relationship with your partner without the children involved, if that’s ok, look at the positives he brings to the children as a whole, look at the past and see if there is a future, marriage and blended families are difficult. But it might not be worth throwing it away.