IMO sex with your partner, as long as its in a meaningful relationship and not just a one night kinda thing, just helps to support you getting back to "normal". The end goal is surely to have a healthy sexual relationship rather than PMO.
Agreed, on the other hand I heard opinion that regular sex breaks your nofap marathon and motivation.
From my personal experience it's the opposite. Regular sex not only helps with the sexual build up but keeps me grounded as to why I don't want PMO to take over.
You have the choice. Some people discover that taking a brief break from all sexual stimulation allows the brain to rest and recover more quickly. However, whether or not there is sex involved, daily affectionate touch is always beneficial. However, if a reboot is taking a while, having sex with a partner can occasionally help libido get back to normal.
A lot of people here find that sex with a partner is becoming less enjoyable due to problems caused by porn use. Still more have difficulty finding a partner for the same reason. Some people want to eschew any form of sex, i.e. become completely celibate, for whatever reason. Keep track of your urges and relapses. Is it happening the morning after sex for example? (chaser effect) or is it more likely to happen after a few days of no sex? If you have a partner or wife and you are having enjoyable and normal sex (i.e. not having PIED, not fantasising about the porn you are watching, etc), and chaser effect isn't an issue for you, then I see no reason that you can't carry on while doing nofap.
Depends on what works best for you. And you might not know until you try. Personally I would say go for it if you think its a healthy relationship. One of the major draws to NoFap (besides personal development, self control and more mental stability) is to be more sexually connected. It's not to hold in cum and try to be enlightened/ ever powerful being or whatever hyped up outlandish stuff some people on this forum talk about in regards to retaining. To me its part of a healthy life to have sexual connection with your partner. In the end, do whatever works best for you.
As long as you're not watching porn, I'd say you're making progress. The only thing I've seen from other guys is that sometimes sex keeps them from needing to learn other methods of coping to stay clean, so if the relationship/sex ends, they aren't prepared and relapse. If you want to try taking a period of abstinence, talk to your partner about it. Make sure that you are both aware of each other's needs and try to work on a solution.