These days you could have a "dating relationship" as an experience which could be broken up if there were a lack of fulfillment on the part of the Aries man or Capricorn woman. The second part of the question seems to be focusing not on "dating" or "marriage", but a more REAL LIFE situational question. since you have not disclosed the custodial angle, (i.e. male has kid or kids, female has kid or kids, or kids from previous relationships join in a "modern family"---and then a new kid is born from both you, I must conclude that you are asking for a basic astro opinion.
So, a straight astro opinion would be that an Aries Man could be highly attractive to a Capricorn woman if he has a stable career and a record of strong steady employment. Sure, he could be romantic, high energy and very interesting to listen to.
Cap Female should ask, after weather he's got a GOOD job; the next would be does he listen to you---does he respect you---and when you become quiet or give your serious Cap opinion on a marital or familial issue, does he listen or dismiss you because you don't have as big a personality as he does. Does he intimidate the Cap woman? Is the Cap woman smarter than the Aries male.
The Aries Male should ask if the Female Cap wants to control things financially. He should ask if she appreciates him on a broad basis, not just because of his muscle and youth. Since Cap humor can be a touch irritating, does he put up with that, or is he OK with Cap's slightly superior ways of communicating. NOW for a passing observation about .parenting--DISCUSS PARENTING PHILOSOPHY BIG TIME. Varying POINTS OF VIEW could be the MAKING or the RUINATION of the Aries/Capricorn union.