When I met DP I ran regularly with a club, doing races and half marathons, swam at least once a week, went to the cinema at least once a week to support my interest in film, attended weekly French evening classes, and went away hill-walking at least one weekend each month. If i didn't get enough exercise i'd feel uncomfortable, restless and unhappy. I see some of these activities as integral to and expressions of my identity.
He knew all this when we got together.
Does that mean it is reasonable for me to expect to be able to devote the same amount of time to these activities as I did when single, now that we have a child? No.
Does this mean that it is reasonable for me to presume that my need for exercise and for the mental and social stimulation that these activities offer is more important than his time doing his exercise and other activities, or our time together with dd as a family? No.
So would declaring unilaterally that i will be devoting a significant portion of every weekend to these activities be reasonable? No.
Does it mean that he should understand that these activities are important to me and work with me to accommodate them, fairly, along with his own, in our family life, through careful planning and negotiation? Yes.
Would either of us see acting the WAG to the other's activity as an acceptable substitute for our own activity? No way. It might offer some semblance of joint family time if the activity suited this and both parents could enjoy it but recognising the extent to which the parenting was actually being shared.
So, you would be unreasonable to ask to give up sport entirely. You would be entirely reasonable to expect him to negotiate his 'me' time with you, on the basis that you have equal 'me' time and that shared, enjoyable, family time must also be accommodated and (I think) sometimes takes precedence.
I do think there's a massive double standard in operation in this society about sport and 'me' time. There also exists an assumption in many people's minds that SAHM means 'primary career 24/7', unless an exceptional release from duty is granted, not, as I understand it 'my job during business hours is child care' with parenting at evenings and weekends shared. For those reasons your post, as one example, makes me very cross in a much more general sense.