This Joined Valentine Heart illustrates two principles 1) a joined heart may be joined about a point anywhere in the surface of the heart and 2) you may overcome the difficulty of having sections outside the heart shape by gluing together the two pieces of a heart part before joining.
The heart is joined like any other joined heart. Just identify the joining point, which is at some distance from the “spine”. The slits are not vertical and joining works much easier if you align and fix the two pieces forming each half part of the heart with a little glue near the point, before you join. Also after joining you may prefer to fix the two parts when aligned. Fix the handle with glue in between the two pieces of the half parts.