Yes, our relationship has suffered, but not as badly as some PPs.
Our relationship was pretty solid to begin with and I think that’s why we’re still together and working on things, despite the baby having made everything so much harder.
He has always more than pulled his weight with the housework. (I often wonder why women think - hope? - a lazy partner will change after children arrive, it never seems to happen!) I was already doing more of the “wifework”, specifically emotional labour and organising holidays and social life. Now I feel that the “mental load” is heavier since I’m always thinking about son and everything he needs - on top of everything else - so that’s been difficult and added some stress and resentment on my part.
The main issue though has been extreme sleep deprivation (DS had CMPA and reflux which was undiagnosed for a while) which has affected our mental health and made us much less patient with each other. Plus the we just don’t have the time or energy to relax or have fun together - we’ve fallen into the cliched trap of putting ourselves (as individuals but also our marriage) last, after 1. Baby 2. Work 3. Housework! We are working on carving out some time for ourselves. Better sleep (TOUCH WOOD) is helping.
I know that premarital counselling is a “thing” and I think that pre-TTC counselling should be one too! It’s even more important as imo having a child together is a bigger commitment than marriage. I think it’s crucial to discuss expectations around the key topics: parental leave, how much time does each of you want to take, what do you each want in terms of being a SAHP or doing paid work full or part time, childcare including how you feel about grandparents doing some, current lifestyle and whether either of you needs to change anything (eg reduce time on hobbies or quit smoking or whatever it is), if not yet married do you want to be, do either of you have strong feelings about any particular parenting styles or topics, religion, education etc... I could probably go on!
Anyway DH and I had discussed the main points before our son was born so there were no nasty surprises afterwards, I expect that could be a real sticking point for many couples.