Actions which have the tendency to keep one from his/her obligations should be refrained from. Carnal and marital needs and obligations (Haq-un-Nas) don't have a higher precedence than religious obligations (Haq-ullah).
E.g. to prove the point, obligatory fast don't need husband's consent, while the non-obligatory ones do.
But if one inadvertently gets into a state where one has to perform ablution, but medical conditions and/or environmental conditions don't permit then one should perform the dry ablution (not getting into the details of it) and perform his/her obligations.
Certainly and definitely one shouldn't forgo prayer because of the above mentioned.
What does Quran says about that kind of situation
These are some relevant to your situation:
O ye who believe! Approach not prayers with a mind befogged, until ye can
understand all that ye say,- nor in a state of ceremonial impurity [Except when
travelling on the road], until after washing your whole body. If ye are ill, or on a journey, or one of you cometh from offices of nature, or ye have been in
contact with women, and ye find no water, then take for yourselves clean sand or
earth, and rub therewith your faces and hands. For Allah doth blot out sins and
forgive again and again. (4:43)
O ye who believe! When ye prepare for prayer, wash your faces, and your hands
(and arms) to the elbows; rub your heads (with water); and (wash) your feet to
the ankles. If ye are in a state of ceremonial impurity, bathe your whole body.
But if ye are ill, or on a journey, or one of you cometh from offices of nature,
or ye have been in contact with women, and ye find no water, then take for
yourselves clean sand or earth, and rub therewith your faces and hands. Allah
doth not wish to place you in a difficulty, but to make you clean, and to
complete His favor to you, that ye may be grateful. (5:7)
And what does Allah guides and instruct about prayers:
And be steadfast in prayer; practise regular charity; and bow down your
heads with those who bow down [in worship]. (2:43)
O ye who believe! seek help with patient perseverance and prayer; for Allah
is with those who patiently persevere. (2:153)
Guard strictly your [habit of] prayers, especially the Middle Prayer; and
stand before Allah in a devout [frame of mind]. (2:238)